test(e2e): desktop browser-tabs hides developer toasts on its attached page

The locator handler that dismissed #error-toast could match a toast that closed before its
click, then wait on it until the test timed out (agent-timeline-resume.spec.ts:45 failed every
attempt on this branch). Hiding the toast with CSS keeps it off app actions with no race.

docs/explorer-sidebar.md

@@ -11,7 +11,7 @@ contracts.
 
 ## Panel host contract
 
-Every desktop panel registers its supported `PaneHost` values and presentation. Launchers derive
+Every panel registers its supported `PaneHost` values and presentation. Launchers derive
 fixed-target labels and icons from that registration, filter by host, and never substitute one
 panel type for another. Tab moves reject unsupported destinations, and placement resolves only to
 a compatible pane.
@@ -21,7 +21,10 @@ so a pane’s + menu omits each while that pane already contains it. Closing one
 item available again. Other compatible tabs, including agents, terminals, files, and diffs,
 can move between Explorer and main panes.
 Keep panel implementations independent of either shell. `WorkspacePanelHost` owns mounting and
-retention, while each shell owns its tabs, focus, dragging, resizing, and shortcuts.
+retention. The shared Explorer owns its tab rail; its shared frame owns visibility, activity and
+close-gesture lifetime. Platform adapters own resizing and inset geometry.
+The host keeps three recently used tabs plus modified tabs; unmodified tabs beyond that budget
+can remount. Native retained content stays live, while web chat uses its existing deferred Freeze.
 
 ## Sheets
 
@@ -40,11 +43,11 @@ remounts its panel. Revealing a target that already has a sheet uncovers that sh
 ones above it, except ones holding unsaved work, which stay where they are. Opening a sheet as a tab
 dismisses the sheets above it, since the tab would sit under them. The stack is not persisted.
 
-Sheets are modal and cover the whole compact column, header included. A sheet's header is its drag
+Sheets are modal and cover the whole compact workspace, including the header and Explorer. A sheet's header is its drag
 handle, because the panel scrolls on its own and content panning would fight it. Its trailing rail
 holds icon buttons only (`SheetHeaderIconButton`): Open as tab is the full-screen glyph beside
 Close, so the title keeps its width. The sheets present
-from inside the compact column's `SheetHostScope`, so their panels read the navigator and every
+from the shared workspace's `SheetHostScope`, so their panels read the navigator and every
 workspace provider an ordinary pane has without a context bridge
 ([floating-panels.md Gotcha 6](floating-panels.md#gotcha-6--bottom-sheet-refs-are-not-lifecycle-truth)).
 
@@ -56,12 +59,16 @@ the sheet's tab into a pane, and edits the autosave has not started writing are
 ## Explorer sidebar
 
 `packages/app/src/workspace-tabs/explorer-sidebar.ts` owns show, hide, toggle, and view selection.
-On desktop, the shell is rendered outside the workspace split canvas so it divides the full
-workspace, including the header. It has its own persisted width and resize handle. Main-pane splits
+One Explorer host stays beside the center column across compact overlays and docks. Keep its
+providers and gesture roots at the same React position when width or appearance changes. The
+workspace route preserves panel ancestry during appearance updates. Appearance-dependent leaves
+subscribe to theme changes; the file editor reconfigures its existing editor theme compartment.
+Ordinary leaf routes retain the stack appearance policy.
+The shell is outside the workspace split canvas so it divides the full workspace, including the header. It has its own persisted width and resize handle. Main-pane splits
 never read or modify that width.
 
 `packages/app/src/workspace-tabs/open-supporting-view.ts` owns semantic Changes and pull-request
-opens. Compact and wide native layouts select the matching Explorer tab. Desktop Changes opens
+opens. Compact and wide native layouts select the matching workspace tab in Explorer. Desktop Changes opens
 follow the shared diff preference. Desktop pull requests use their Main panel, On the side, or
 Explorer sidebar setting. Automatic PR discovery follows that preference once per workspace without
 interrupting the user's work. Closing the tab opts that workspace out of future automatic opens,
@@ -76,18 +83,37 @@ literal `"explorer"` pane id and `explorerPaneIdByWorkspace` key for compatibili
 
 Explorer uses the shared workspace tab row and ordinary tab context menus. Files and Changes
 hide their close buttons through the panel manifest; close them from the tab context menu.
-Other tabs reveal the close control on hover. The + menu opens compatible panels in the dock and
-omits Agent and terminal profiles. Agents and terminals can still be dragged into Explorer.
+Other tabs reveal the close control on hover. The + menu opens compatible panels in the dock, including Agent and terminal profiles.
+Web also supports dragging agents and terminals into Explorer.
 Bulk-close actions apply only to the dock's tabs. Explorer tabs can be reordered and dragged
 between compatible panes, but the dock cannot be split or maximized. Selecting an Explorer tab
-does not change workspace focus.
+does not change workspace focus. Web dragging shares the workspace drag scope; compact layouts
+accept only reordering inside the source pane.
 
-Cmd+E shows or hides Explorer without changing its selected view. Compact layouts use the combined
-full-screen Explorer overlay for Changes, Files, and pull requests, and close it after a file opens. Compact Changes has no tree rail; its overview is the Jump to file action (`packages/app/src/git/jump-to-file/`), a sheet over the same changed-files tree the desktop rail renders.
-Wide native layouts without pane splits use the same combined content in a resizable inline dock;
-opening a file leaves that dock visible. Both presentations keep their selection in the panel store
-and reuse the layout store's per-workspace Explorer width. They do not create a second Explorer
-lifecycle.
+Cmd+E shows or hides Explorer without changing its selected view. All layouts use the same
+workspace tabs, launcher, and panel host. Below 600 points the shell is the swipeable Explorer
+overlay; at 600 points and above it reserves width beside the workspace. Native docking keeps its
+touch resize handle. Full workspace splits remain a separate web-only capability.
+
+The dock reserves at least 240 points and the workspace 360. App navigation yields when it cannot
+share the remaining width with both. This keeps a portrait tablet from rendering three unusably
+narrow columns; widening restores navigation without changing its saved open state.
+
+Compact panel gestures own overlay visibility; the workspace layout owns its tab selection and
+contents on every platform. Explicit pane destinations bypass compact sheet placement, so choosing
+a panel in Explorer's + menu keeps it there. Ordinary compact file and subagent look-ups still use
+the sheet policy. Resolving an existing main tab reveals center immediately; a new file sheet
+keeps Explorer underneath and closing the sheet uncovers it. Semantic navigation resolves the
+actual destination before revealing it, including deduplicated targets.
+
+Compact overlay selection and saved dock visibility are independent. Folding changes geometry,
+not either mode’s visibility intent. Native workspace retention remains one workspace; web retains
+up to ten with its existing inactive TTL.
+
+PR discovery belongs to the active workspace: split layouts discover while active, and other
+layouts discover while Explorer is active. The rail requests summary status; selected visible PR
+content also requests timeline data. Inactive consumers read cached data without request demand.
+Discovery uses ordinary PR tabs and their existing once-per-workspace close opt-out.
 
 ## Side pane
 

docs/expo-router.md

@@ -157,7 +157,9 @@ a small `withUnistyles` boundary without subscribing the route tree itself to
 every Unistyles runtime update.
 
 Navigators keep their identity across appearance changes. `ThemedStack` remounts
-each screen's content below the native stack when appearance tokens change; a
+each ordinary screen's content below the native stack when appearance tokens change.
+Workspace screens own retained panel lifetimes and update appearance at their
+leaves through `screenOwnedAppearance` ([Explorer](explorer-sidebar.md)). A
 keyed wrapper above a stack remounts the stack itself, and Android crashes when
 that happens while a FragmentManager transaction is running, which settings
 hydration at startup makes likely. A screen that mounts a nested navigator (the

docs/mobile-panels.md

@@ -32,7 +32,9 @@ The UI worklet owns transient motion:
 
 React publishes the active panel only when the canonical target and the UI-thread position agree at
 the final anchor. Retained content never observes gesture previews, progress, or an unsettled target.
-The gesture hosts stay mounted. Native worklets own overlay opacity and pointer events while
+The gesture hosts stay mounted. The Gesture Handler web patch keeps initially disabled hosts
+from capturing paragraph pointers; that capture confines browser selection to its starting paragraph.
+Native worklets own overlay opacity and pointer events while
 React owns settled panel activity and accessibility. Keep hidden native overlays laid out: collapsing
 their scroll ranges makes Android spring retained offsets back to zero during touch cancellation or
 release. Native panel hosts and their dependent draggable lists

docs/plugins.md

@@ -556,6 +556,24 @@ one section's order from built-ins, plugin groups, and the section's preference
   remembers under its own key. It shares header ids and the `plugin:<pluginId>:<id>` settings key
   with new-API items.
 
+## Contribute file panels
+
+Client `addFilePanel` registrations become the body of a file tab. The tab stats the file, picks a
+panel, and mounts it with a `PluginFile` handle; the panel reads, shows its own `Loading`, writes,
+and resolves conflicts. The bar only switches panels and shows the dot the panel sets through
+`tab.setModified`. Built-in panels (Markdown, HTML, Image, and Source, Paseo's editor) take the
+same handle as plugin panels, so a fix to reading, watching, or writing lands in one place:
+`packages/app/src/file-panels/file/`. Do not add a host-side read or loading gate for one panel;
+make that panel faster instead. Source highlights a large file on native in idle-time slices,
+the lines around the opening line first.
+
+The handle checks every write against the version it last read or wrote, so two panels or a panel
+and an agent cannot silently overwrite each other. The daemon reports the file's kind (text,
+image, binary) with its stat from a bounded sniff, which is how Source claims text files without a
+read. See the [public file panel reference](../public-docs/plugins/reference.md#file-panels) for
+the author API, selection, `DocumentFrame`, and the version requirement. The examples live in
+`plugin-examples/pdf-panel` and `plugin-examples/markdown-panel`.
+
 ## Contribute buttons
 
 Header buttons and composer pills share the client-only descriptor and registration lifecycle in

docs/testing.md

@@ -193,7 +193,7 @@ Test suites in this repo are heavy. Running them in bulk freezes the machine, es
 - Playwright specs that exercise only the daemon import `daemonTest` from the shared fixtures so they do not create a browser context or page.
 - Helpers that create projects or workspaces own those records until cleanup. Their clients remove the daemon project on close, and an automatic fixture fails any test that still leaks a project record. Deleting only the temporary directory is not cleanup. Agent helpers pass the intended `workspaceId` through to agent creation; they never infer ownership from `cwd`.
 - Tests whose subject is daemon-global state, such as an empty history or daemon restart, start a dedicated host explicitly. Filenames and directories describe product behavior, never execution order or isolation mechanics.
-- Global setup accepts Metro as ready only when `/status` returns `packager-status:running`, then fetches the document's scripts so the cold bundle compilation finishes before Playwright's per-test timeout starts. A generic TCP listener is not sufficient readiness evidence. The browser suite uses direct local daemon connections and does not start a relay.
+- Global setup accepts Metro as ready only when `/status` returns `packager-status:running`, then fetches the document's scripts so the cold bundle compilation finishes before Playwright's per-test timeout starts. A generic TCP listener is not sufficient readiness evidence. The browser suite uses direct local daemon connections and does not start a relay. Automated Metro launches set `EXPO_UNSTABLE_HEADLESS=1` so Expo does not download the native DevTools shell into temporary test homes; its read-only cache breaks teardown. Browser fixtures and the standalone Electron browser runner share the developer-toast dismissal helper while retaining console logs. A pointer click moves hover away from the tested control and stalls behind app modal backdrops.
 - The app Playwright harness boots on Windows as well as POSIX. Spawn Node entrypoints through `process.execPath`, not `npx` or `node_modules/.bin` shims: Node refuses to spawn `.cmd` or `.bat` without `shell: true`, and shell mode concatenates argv without escaping and sends kill signals to `cmd.exe` instead of the real child.
 - Teardown kills the process tree, because a Windows signal reaches only the direct child and leaves forked workers holding the listening port.
 - The `asdf`-backed local Elixir relay stays POSIX-only, so the `relay-deployment` Playwright project is unavailable on Windows.

nix/npm-deps.hash

@@ -1 +1 @@
-sha256-ObBdUmNSW+vDjzA7EbCDfZrB0nYDmcWmWe+UCoTMh/M=
+sha256-7B/Zyo/DaHdd3PVq8Hn1HG+x+wLdZBVxgx/cbtaM/S8=

package.json

@@ -137,16 +137,21 @@
     "oxlint-tsgolint": "^0.22.1",
     "patch-package": "^8.0.1",
     "playwright": "^1.56.1",
+    "react-dom": "19.2.3",
     "typescript": "^5.9.3",
     "ws": "^8.20.0"
   },
   "overrides": {
     "@codemirror/language": "6.12.4",
     "@codemirror/view": "6.43.6",
+    "expo": "~57.0.30",
+    "expo-router": "~57.0.28",
     "lightningcss": "1.30.1",
-    "react": "19.1.0",
-    "react-dom": "19.1.0",
-    "react-native-reanimated": "4.3.1",
-    "react-native-worklets": "0.8.3"
+    "react": "19.2.3",
+    "react-dom": "19.2.3",
+    "react-native": "0.86.3",
+    "react-native-gesture-handler": "~2.32.0",
+    "react-native-reanimated": "4.5.1",
+    "react-native-worklets": "0.10.1"
   }
 }

packages/app/app.config.js

@@ -171,6 +171,7 @@ export default {
       [
         "expo-build-properties",
         {
+          ios: { enableSceneSupport: true },
           android: {
             minSdkVersion: 29,
             kotlinVersion: "2.1.20",

packages/app/e2e/browser/add-changed-file-to-chat.spec.ts

@@ -2,48 +2,56 @@ import { mkdir, writeFile } from "node:fs/promises";
 import path from "node:path";
 import { test, expect, type Page } from "../support/fixtures";
 import { seedMockAgentWorkspace, openAgentRoute } from "../support/helpers/mock-agent";
-import { openChangesPanel } from "../support/helpers/workspace-tabs";
+import { openChangesPanel, openChangesTreePanel } from "../support/helpers/workspace-tabs";
 
 function visibleComposer(page: Page) {
   return page.locator("textarea[data-composer-input]").filter({ visible: true }).first();
 }
 
-test("adds a changed file to the focused chat without replacing its composer draft", async ({
-  page,
-}) => {
-  const workspace = await seedMockAgentWorkspace({
-    repoPrefix: "add-file-to-chat-",
-    title: "Target chat",
-  });
-  const relativePath = "src/changed file.ts";
-
-  try {
-    await mkdir(path.join(workspace.cwd, "src"), { recursive: true });
-    await writeFile(path.join(workspace.cwd, relativePath), "export const changed = true;\n");
-    await workspace.client.checkoutRefresh(workspace.cwd);
-
-    await page.setViewportSize({ width: 1400, height: 900 });
-    await openAgentRoute(page, {
-      workspaceId: workspace.workspaceId,
-      agentId: workspace.agentId,
+for (const width of [1400, 390]) {
+  test(`adds a changed file to the focused chat without replacing its composer draft at ${width}px`, async ({
+    page,
+  }) => {
+    const workspace = await seedMockAgentWorkspace({
+      repoPrefix: "add-file-to-chat-",
+      title: "Target chat",
     });
+    const relativePath = "src/changed file.ts";
 
-    const agentComposer = visibleComposer(page);
-    await expect(agentComposer).toBeEditable({ timeout: 30_000 });
-    await agentComposer.fill("Preserve this thought");
+    try {
+      await mkdir(path.join(workspace.cwd, "src"), { recursive: true });
+      await writeFile(path.join(workspace.cwd, relativePath), "export const changed = true;\n");
+      await workspace.client.checkoutRefresh(workspace.cwd);
 
-    await openChangesPanel(page);
-    const changedFile = page.getByText("changed file.ts", { exact: true }).first();
-    await expect(changedFile).toBeVisible({ timeout: 30_000 });
-    await page.getByTestId("diff-file-0-toggle").click({ button: "right" });
-    await page.getByTestId("diff-file-0-add-to-chat").click();
+      await page.setViewportSize({ width, height: 900 });
+      await openAgentRoute(page, {
+        workspaceId: workspace.workspaceId,
+        agentId: workspace.agentId,
+      });
 
-    const attachment = page.getByTestId("composer-workspace-file-attachment-pill");
-    await expect(attachment).toContainText("changed file.ts");
-    await expect(attachment).toContainText(relativePath);
-    await expect(agentComposer).toHaveValue("Preserve this thought");
-    await expect(agentComposer).toBeFocused();
-  } finally {
-    await workspace.cleanup();
-  }
-});
+      const agentComposer = visibleComposer(page);
+      await expect(agentComposer).toBeEditable({ timeout: 30_000 });
+      await agentComposer.fill("Preserve this thought");
+
+      if (width < 600) await openChangesTreePanel(page);
+      else await openChangesPanel(page);
+      const changedFile = page.getByTestId("diff-file-0-toggle");
+      await expect(changedFile).toBeVisible({ timeout: 30_000 });
+      await page.getByTestId("diff-file-0-toggle").click({ button: "right" });
+      await page.getByTestId("diff-file-0-add-to-chat").click();
+
+      const attachment = page.getByTestId("composer-workspace-file-attachment-pill");
+      if (width < 600)
+        await expect(
+          page.getByTestId("workspace-explorer-sidebar").filter({ visible: true }),
+        ).toHaveCount(0);
+      await expect(attachment).toContainText("changed file.ts");
+      await expect(attachment).toContainText(relativePath);
+      await expect(agentComposer).toHaveValue("Preserve this thought");
+      if (width >= 600) await expect(agentComposer).toBeFocused();
+      else await expect(agentComposer).toBeEditable();
+    } finally {
+      await workspace.cleanup();
+    }
+  });
+}

packages/app/e2e/browser/changes-pane.spec.ts

@@ -833,13 +833,15 @@ test("compact Changes keeps its actions compact and menu-only", async ({ page })
   await openWorkspaceChanges(page, workspace);
   await page.setViewportSize({ width: 480, height: 900 });
 
-  const compactChangesTab = page.getByTestId("explorer-tab-changes").filter({ visible: true });
+  const compactChangesTab = page
+    .getByTestId("workspace-tab-changes_tree")
+    .filter({ visible: true });
   if (!(await compactChangesTab.isVisible())) {
     await page.getByTestId("workspace-explorer-toggle").first().click();
   }
   await expect(compactChangesTab).toBeVisible();
   await compactChangesTab.click();
-  const compactExplorer = page.getByTestId("explorer-content-area").filter({ visible: true });
+  const compactExplorer = page.getByTestId("workspace-explorer-sidebar").filter({ visible: true });
   await expect(compactExplorer.getByTestId("changes-header")).toBeVisible();
 
   const actions = compactExplorer.getByTestId("changes-actions-menu-trigger");
@@ -876,6 +878,27 @@ test("compact Changes keeps its actions compact and menu-only", async ({ page })
   ).toContainText("Scroll long lines");
 });
 
+test("compact Explorer renders inline hunks with a saved tree-only desktop preference", async ({
+  page,
+}) => {
+  const workspace = await createWorkspaceWithMountedTabDiff();
+  await page.addInitScript(
+    ({ key }) => {
+      localStorage.setItem(key, JSON.stringify({ inlineDiff: false, layout: "split" }));
+    },
+    { key: CHANGES_PREFERENCES_KEY },
+  );
+  const explorer = await openCompactChanges(page, workspace);
+  await expect(explorer.getByTestId("git-diff-canvas")).toBeVisible();
+  await expect(explorer.getByTestId("diff-file-0-toggle")).toBeVisible();
+  await explorer.getByTestId("diff-file-0-toggle").click({ button: "right" });
+  page.once("dialog", (dialog) => dialog.accept());
+  await page.getByTestId("diff-file-0-revert").click();
+  await expect
+    .poll(() => readFile(path.join(workspace.repoPath, "src/use-mounted-tab-set.ts"), "utf8"))
+    .toBe(BEFORE);
+});
+
 test("compact Changes jumps to a file from the changed-files sheet", async ({ page }) => {
   const workspace = await createWorkspaceWithMountedTabDiff({ includeNestedFolders: true });
   await useUnwrappedDiffLines(page);
@@ -1674,10 +1697,10 @@ async function openCompactChanges(page: Page, workspace: DirtyWorkspace): Promis
   await page.goto(buildHostWorkspaceRoute(getServerId(), workspace.id));
   await page.reload();
   await page.getByTestId("workspace-explorer-toggle").first().click();
-  const changesTab = page.getByTestId("explorer-tab-changes").filter({ visible: true });
+  const changesTab = page.getByTestId("workspace-tab-changes_tree").filter({ visible: true });
   await expect(changesTab).toBeVisible({ timeout: 30_000 });
   await changesTab.click();
-  const explorer = page.getByTestId("explorer-content-area").filter({ visible: true });
+  const explorer = page.getByTestId("workspace-explorer-sidebar").filter({ visible: true });
   await expect(explorer.getByTestId("changes-header")).toBeVisible({ timeout: 30_000 });
   return explorer;
 }

packages/app/e2e/browser/compact-git-actions-menu.spec.ts

@@ -45,10 +45,10 @@ async function openCompactActionsMenu(page: Page, workspaceId: string) {
   await page.goto(buildHostWorkspaceRoute(getServerId(), workspaceId));
   await page.reload();
   await page.getByTestId("workspace-explorer-toggle").first().click();
-  const changesTab = page.getByTestId("explorer-tab-changes").filter({ visible: true });
+  const changesTab = page.getByTestId("workspace-tab-changes_tree").filter({ visible: true });
   await expect(changesTab).toBeVisible({ timeout: 30_000 });
   await changesTab.click();
-  const explorer = page.getByTestId("explorer-content-area").filter({ visible: true });
+  const explorer = page.getByTestId("workspace-explorer-sidebar").filter({ visible: true });
   await expect(explorer.getByTestId("changes-header")).toBeVisible({ timeout: 30_000 });
 
   const trigger = explorer.getByTestId("changes-actions-menu-trigger");

packages/app/e2e/browser/composer-diff-stat.spec.ts

@@ -125,7 +125,7 @@ test("composer diff stat opens the compact explorer instead of a Changes tab", a
     });
 
     const closeExplorer = page
-      .getByTestId("explorer-header")
+      .getByTestId("workspace-explorer-sidebar")
       .getByRole("button", { name: "Close Explorer sidebar" });
     await expect(closeExplorer).not.toBeInViewport();
 
@@ -809,7 +809,7 @@ async function expectUnmatchedFeedback(page: Page) {
 }
 
 function compactReviewSurface(page: Page) {
-  return page.getByTestId("explorer-content-area").filter({ visible: true });
+  return page.getByTestId("workspace-explorer-sidebar").filter({ visible: true });
 }
 async function openCompactReviewExplorer(
   page: Page,
@@ -847,7 +847,10 @@ async function scrollReviewToLastLine(page: Page) {
 
 async function revealCompactChanges(page: Page) {
   await page.getByTestId("workspace-explorer-toggle").first().click();
-  await page.getByTestId("explorer-header").getByText("Changes", { exact: true }).click();
+  await page
+    .getByTestId("workspace-explorer-sidebar")
+    .getByTestId("workspace-tab-changes_tree")
+    .click();
   await expect(compactReviewSurface(page).getByTestId("diff-file-0-body")).toBeVisible();
 }
 async function expectReviewEditorBody(page: Page, body: string) {

packages/app/e2e/browser/explorer-sidebar.spec.ts

@@ -1,3 +1,7 @@
+import { seedMockAgentWorkspace, openAgentRoute } from "../support/helpers/mock-agent";
+import { writeFile } from "node:fs/promises";
+import { openFileFromExplorer } from "../support/helpers/file-explorer";
+import { openSettingsSection, clickSettingsBackToWorkspace } from "../support/helpers/settings";
 import { expect, test } from "../support/fixtures";
 import {
   gotoWorkspace,
@@ -136,10 +140,9 @@ test("Explorer keeps Files and Changes close actions in the context menu", async
       await explorer.getByRole("button", { name: "New tab", exact: true }).click();
       const menu = page.getByTestId("workspace-new-tab-menu").filter({ visible: true });
       await expect(menu).toBeVisible();
-      await expect(menu.getByRole("menuitem", { name: /^Agent/ })).toHaveCount(0);
+      await expect(menu.getByRole("menuitem", { name: /^Agent/ })).toHaveCount(1);
       await expect(menu.getByRole("menuitem", { name: /^Files/ })).toHaveCount(0);
       await expect(menu.getByRole("menuitem", { name: /^Changes/ })).toHaveCount(0);
-      await expect(menu.getByText("Terminal profiles", { exact: true })).toHaveCount(0);
       await expect(menu.getByRole("menuitem", { name: /^Terminal/ })).toBeVisible();
       const entries = await menu.getByRole("menuitem").allTextContents();
       expect(entries.findIndex((entry) => entry.startsWith("Terminal"))).toBeLessThan(
@@ -191,13 +194,11 @@ test("Explorer keeps Files and Changes close actions in the context menu", async
   }
 });
 
-async function dragAgentIntoExplorer(
+async function dragTabIntoExplorer(
   page: Parameters<typeof ensureExplorerSidebar>[0],
-  agentId: string,
+  tabId: string,
 ) {
-  const source = page
-    .getByTestId("workspace-pane-main")
-    .getByTestId(`workspace-tab-agent_${agentId}`);
+  const source = page.getByTestId("workspace-pane-main").getByTestId(`workspace-tab-${tabId}`);
   const destination = explorerSidebar(page).getByTestId("workspace-tab-files");
   const sourceBox = await source.boundingBox();
   const destinationBox = await destination.boundingBox();
@@ -213,7 +214,7 @@ async function dragAgentIntoExplorer(
   await page.mouse.up();
 }
 
-test("agents can still be dragged into Explorer when absent from its + menu", async ({
+test("moves agents into Explorer and keeps the shared Agent launcher available", async ({
   page,
 }, testInfo) => {
   const workspace = await seedWorkspace({ repoPrefix: "explorer-agent-drag-" });
@@ -230,14 +231,13 @@ test("agents can still be dragged into Explorer when absent from its + menu", as
     });
     const main = page.getByTestId("workspace-pane-main");
     await expect(main.getByTestId(`workspace-tab-agent_${agent.id}`)).toBeVisible();
-    await dragAgentIntoExplorer(page, agent.id);
+    await dragTabIntoExplorer(page, `agent_${agent.id}`);
     await expect(explorer.getByTestId(`workspace-tab-agent_${agent.id}`)).toBeVisible();
     await expect(main.getByTestId(`workspace-tab-agent_${agent.id}`)).toHaveCount(0);
     await explorer.getByRole("button", { name: "New tab", exact: true }).click();
     const menu = page.getByTestId("workspace-new-tab-menu").filter({ visible: true });
     await expect(menu).toBeVisible();
-    await expect(menu.getByRole("menuitem", { name: /^Agent/ })).toHaveCount(0);
-    await expect(menu.getByText("Terminal profiles", { exact: true })).toHaveCount(0);
+    await expect(menu.getByRole("menuitem", { name: /^Agent/ })).toHaveCount(1);
     await page.keyboard.press("Escape");
     await testInfo.attach("agent-in-explorer", {
       body: await page.screenshot(),
@@ -247,3 +247,273 @@ test("agents can still be dragged into Explorer when absent from its + menu", as
     await workspace.cleanup();
   }
 });
+
+test("tablet prototype keeps Explorer tabs when resizing down to a phone", async ({
+  page,
+}, testInfo) => {
+  const workspace = await seedWorkspace({ repoPrefix: "tablet-explorer-" });
+  try {
+    await page.setViewportSize({ width: 951, height: 669 });
+    await gotoWorkspace(page, workspace.workspaceId);
+    await waitForWorkspaceTabsVisible(page);
+    await ensureExplorerSidebar(page);
+    await expect(
+      explorerSidebar(page).getByRole("button", { name: "Browse workspace files", exact: true }),
+    ).toBeVisible();
+    await page.screenshot({ path: testInfo.outputPath("tablet-951.png") });
+    await openExplorerAgentDraft(page);
+    await page.screenshot({ path: testInfo.outputPath("tablet-agent-draft.png") });
+    await page.setViewportSize({ width: 390, height: 844 });
+    await revealPhoneExplorer(page);
+    await expect(
+      explorerSidebar(page).getByRole("button", { name: "New tab", exact: true }),
+    ).toBeVisible();
+    await page.screenshot({ path: testInfo.outputPath("phone-shared-explorer.png") });
+  } finally {
+    await workspace.cleanup();
+  }
+});
+
+async function openExplorerAgentDraft(page: Parameters<typeof ensureExplorerSidebar>[0]) {
+  await explorerSidebar(page).getByRole("button", { name: "New tab", exact: true }).click();
+  await page.getByRole("menuitem", { name: /^Agent/ }).click();
+  await expect(explorerSidebar(page).getByRole("textbox").first()).toBeVisible();
+}
+
+async function revealPhoneExplorer(page: Parameters<typeof ensureExplorerSidebar>[0]) {
+  await page.getByRole("button", { name: "Open Explorer sidebar", exact: true }).click();
+  await expect(explorerSidebar(page)).toBeVisible();
+  await expect(
+    explorerSidebar(page).getByRole("button", { name: "Close Explorer sidebar", exact: true }),
+  ).toBeInViewport({ ratio: 1 });
+}
+
+async function cycleWorkspaceTheme(page: Parameters<typeof ensureExplorerSidebar>[0]) {
+  await page.keyboard.press("Control+Alt+t");
+}
+
+test("retains the Explorer host through appearance changes and folding", async ({ page }) => {
+  const workspace = await seedWorkspace({ repoPrefix: "explorer-lifetime-" });
+  try {
+    await gotoWorkspace(page, workspace.workspaceId);
+    const explorer = await ensureExplorerSidebar(page);
+    await openFilesPanel(page);
+    const host = await explorer.elementHandle();
+    if (!host) throw new Error("Explorer must be mounted before changing appearance");
+    const previousColor = await explorer.evaluate(
+      (element) => getComputedStyle(element).backgroundColor,
+    );
+    await cycleWorkspaceTheme(page);
+    await expect
+      .poll(() => explorer.evaluate((element) => getComputedStyle(element).backgroundColor))
+      .not.toBe(previousColor);
+    expect(await host.evaluate((element) => element.isConnected)).toBe(true);
+    await page.setViewportSize({ width: 390, height: 844 });
+    await ensureExplorerSidebar(page);
+    expect(await host.evaluate((element) => element.isConnected)).toBe(true);
+    await page.setViewportSize({ width: 1280, height: 900 });
+    await expect(explorer).toBeVisible();
+    expect(await host.evaluate((element) => element.isConnected)).toBe(true);
+  } finally {
+    await workspace.cleanup();
+  }
+});
+
+async function reorderCompactExplorerTabs(page: Parameters<typeof ensureExplorerSidebar>[0]) {
+  const explorer = explorerSidebar(page);
+  const files = explorer.getByTestId("workspace-tab-files");
+  const changes = explorer.getByTestId("workspace-tab-changes_tree");
+  const source = await changes.boundingBox();
+  const target = await files.boundingBox();
+  if (!source || !target) throw new Error("Explorer tabs must be visible to reorder");
+  await page.mouse.move(source.x + source.width / 2, source.y + source.height / 2);
+  await page.mouse.down();
+  await page.mouse.move(source.x + source.width / 2 - 12, source.y + source.height / 2);
+  await page.mouse.move(target.x + 3, target.y + target.height / 2, { steps: 20 });
+  await page.mouse.up();
+  await expect
+    .poll(async () => {
+      const afterFiles = await files.boundingBox();
+      const afterChanges = await changes.boundingBox();
+      return Boolean(afterFiles && afterChanges && afterChanges.x < afterFiles.x);
+    })
+    .toBe(true);
+}
+
+test("reorders compact Explorer tabs with a pointer without changing selection", async ({
+  page,
+}) => {
+  const workspace = await seedWorkspace({ repoPrefix: "explorer-compact-drag-" });
+  try {
+    await gotoWorkspace(page, workspace.workspaceId);
+    await page.setViewportSize({ width: 390, height: 844 });
+    await openFilesPanel(page);
+    await reorderCompactExplorerTabs(page);
+    await expect(
+      explorerSidebar(page).getByRole("button", { name: "Browse workspace files", exact: true }),
+    ).toHaveAttribute("aria-selected", "true");
+  } finally {
+    await workspace.cleanup();
+  }
+});
+
+// Exercise appearance at its consumers while the real workspace navigator retains the panels.
+test("updates populated code and diff appearance without losing the editor instance or draft", async ({
+  page,
+}) => {
+  const workspace = await seedWorkspace({ repoPrefix: "explorer-populated-appearance-" });
+  const source = Array.from(
+    { length: 120 },
+    (_, index) => `export const line${index} = "retained ${index}";`,
+  ).join("\n");
+  try {
+    await writeFile(`${workspace.repoPath}/appearance.ts`, source);
+    await page.addInitScript(() => {
+      localStorage.setItem(
+        "@paseo:app-settings",
+        JSON.stringify({ codeFontSize: 13, theme: "light" }),
+      );
+      localStorage.setItem(
+        "@paseo:changes-preferences",
+        JSON.stringify({ inlineDiff: true, layout: "unified" }),
+      );
+    });
+    await gotoWorkspace(page, workspace.workspaceId);
+    await openFilesPanel(page);
+    await openFileFromExplorer(page, "appearance.ts");
+    const editor = page.getByTestId("file-source-editor").filter({ visible: true });
+    const text = editor.locator(".cm-content");
+    await expect(text).toBeVisible();
+    await text.fill(`${source}\n// unsaved local edit`);
+    const instance = await editor.elementHandle();
+    const scroller = editor.locator(".cm-scroller");
+    await scroller.evaluate((node) => {
+      node.scrollTop = 400;
+    });
+    const scrollBefore = await scroller.evaluate((node) => node.scrollTop);
+    await explorerSidebar(page).getByTestId("workspace-tab-changes_tree").click();
+    const diff = explorerSidebar(page).getByTestId("git-diff-canvas");
+    await expect(diff).toBeVisible();
+    await page.keyboard.press("Control+,");
+    await openSettingsSection(page, "appearance");
+    await page.getByLabel("Code font size", { exact: true }).fill("19");
+    await page.getByLabel("Code font size", { exact: true }).press("Tab");
+    await clickSettingsBackToWorkspace(page);
+    await expect(text).toHaveCSS("font-size", "19px");
+    expect(await instance!.evaluate((node) => node.isConnected)).toBe(true);
+    await expect(text).toContainText("unsaved local edit");
+    expect(await scroller.evaluate((node) => node.scrollTop)).toBe(scrollBefore);
+    await expect(diff).toHaveCSS("font-size", "19px");
+    await cycleWorkspaceTheme(page);
+    expect(await instance!.evaluate((node) => node.isConnected)).toBe(true);
+    await expect(text).toContainText("unsaved local edit");
+    await dragTabIntoExplorer(page, "file_appearance.ts");
+    await expect(explorerSidebar(page).getByTestId("file-source-editor")).toBeVisible();
+    const explorerEditor = await explorerSidebar(page)
+      .getByTestId("file-source-editor")
+      .elementHandle();
+    await text.fill(`${source}\n// retained Explorer edit`);
+    await page.setViewportSize({ width: 390, height: 844 });
+    await ensureExplorerSidebar(page);
+    await page.setViewportSize({ width: 1280, height: 900 });
+    expect(await explorerEditor!.evaluate((node) => node.isConnected)).toBe(true);
+    await expect(text).toContainText("retained Explorer edit");
+  } finally {
+    await workspace.cleanup();
+  }
+});
+
+test("retains populated Explorer chat and terminal attachments through appearance, hide and fold", async ({
+  page,
+}) => {
+  const workspace = await seedMockAgentWorkspace({
+    repoPrefix: "explorer-chat-appearance-",
+    title: "Retained chat",
+    initialPrompt: "Show the retention marker",
+    featureValues: {
+      mockAssistantResponse: "Explorer populated paragraph.\n\n```ts\nconst retained = 42;\n```",
+    },
+  });
+  const attaches: string[] = [];
+  page.on("websocket", (socket) =>
+    socket.on("framesent", (frame) => {
+      if (typeof frame.payload !== "string") return;
+      try {
+        const message = JSON.parse(frame.payload).message;
+        if (message?.type === "subscribe_terminal_request") attaches.push(message.terminalId);
+      } catch {
+        /* Binary terminal traffic is not a JSON request. */
+      }
+    }),
+  );
+  try {
+    await openAgentRoute(page, workspace);
+    await ensureExplorerSidebar(page);
+    await dragTabIntoExplorer(page, `agent_${workspace.agentId}`);
+    const explorer = explorerSidebar(page);
+    const paragraph = explorer.getByText("Explorer populated paragraph.", { exact: true });
+    await expect(paragraph).toBeVisible();
+    const composer = explorer.getByRole("textbox", { name: "Message agent..." });
+    await composer.fill("Unsubmitted Explorer draft");
+    const composerNode = await composer.elementHandle();
+    await page.keyboard.press("Control+,");
+    await openSettingsSection(page, "appearance");
+    await page.getByLabel("Content font size", { exact: true }).fill("20");
+    await page.getByLabel("Content font size", { exact: true }).press("Tab");
+    await clickSettingsBackToWorkspace(page);
+    await expect(paragraph).toHaveCSS("font-size", "20px");
+    expect(await composerNode!.evaluate((node) => node.isConnected)).toBe(true);
+    await expect(composer).toHaveValue("Unsubmitted Explorer draft");
+    const previousColor = await paragraph.evaluate((node) => getComputedStyle(node).color);
+    await cycleWorkspaceTheme(page);
+    await expect
+      .poll(() => paragraph.evaluate((node) => getComputedStyle(node).color))
+      .not.toBe(previousColor);
+    await explorer.getByRole("button", { name: "New tab", exact: true }).click();
+    await page
+      .getByRole("menuitem", { name: /^Terminal/ })
+      .first()
+      .click();
+    const terminal = explorer.getByTestId("terminal-surface");
+    await expect(terminal).toBeVisible();
+    await expect.poll(() => attaches.length).toBe(1);
+    const terminalNode = await terminal.elementHandle();
+    await page.getByTestId("workspace-explorer-toggle").first().click();
+    await ensureExplorerSidebar(page);
+    await page.setViewportSize({ width: 390, height: 844 });
+    await ensureExplorerSidebar(page);
+    await page.setViewportSize({ width: 1280, height: 900 });
+    await cycleWorkspaceTheme(page);
+    expect(await terminalNode!.evaluate((node) => node.isConnected)).toBe(true);
+    expect(attaches).toHaveLength(1);
+    await explorer.getByTestId(`workspace-tab-agent_${workspace.agentId}`).click();
+    expect(await composerNode!.evaluate((node) => node.isConnected)).toBe(true);
+    await expect(composer).toHaveValue("Unsubmitted Explorer draft");
+    await expect(paragraph).toHaveCSS("font-size", "20px");
+  } finally {
+    await workspace.cleanup();
+  }
+});
+
+test("compact file sheets cover Explorer and return to its retained file list", async ({
+  page,
+}) => {
+  const workspace = await seedWorkspace({ repoPrefix: "explorer-sheet-layer-" });
+  try {
+    await writeFile(`${workspace.repoPath}/sheet-marker.txt`, "Explorer sheet marker\n");
+    await gotoWorkspace(page, workspace.workspaceId);
+    await page.setViewportSize({ width: 390, height: 844 });
+    const explorer = await ensureExplorerSidebar(page);
+    await openFilesPanel(page);
+    const host = await explorer.elementHandle();
+    await openFileFromExplorer(page, "sheet-marker.txt");
+    await expect(page.getByText("Explorer sheet marker", { exact: true })).toBeVisible();
+    // A real click also proves the sheet draws above the retained Explorer overlay.
+    await page.getByRole("button", { name: "Close", exact: true }).click();
+    await expect(page.getByText("Explorer sheet marker", { exact: true })).toHaveCount(0);
+    await expect(explorer.getByTestId("file-explorer-tree-scroll")).toBeVisible();
+    expect(await host!.evaluate((node) => node.isConnected)).toBe(true);
+  } finally {
+    await workspace.cleanup();
+  }
+});

packages/app/e2e/browser/file-change-conflicts.spec.ts

@@ -56,45 +56,12 @@ async function replaceEditorText(page: Page, content: string): Promise<void> {
   await editor.type(content);
 }
 
-async function replaceFileAfterDeletionWasObserved(input: {
-  page: Page;
-  gate: Awaited<ReturnType<typeof installDaemonWebSocketGate>>;
-  filePath: string;
-  relativePath: string;
-  content: string;
-}): Promise<void> {
-  const { page, gate, filePath, relativePath, content } = input;
-  // Recreate the observed race without faking file state: the daemon publishes the
-  // deletion, then a real read succeeds after the replacement while its ready event waits.
-  await gate.waitForFileSubscription(relativePath);
-  gate.holdFileReads(relativePath);
-  await unlink(filePath);
-  await gate.waitForHeldFileRead();
-  await expect(fileCallout(page)).toHaveCount(0);
-  gate.releaseHeldFileRead();
-  await expectOnlyFileCallout(page, "File deleted on disk");
-  gate.holdNextReadyFileUpdate(relativePath);
-  await writeFile(filePath, content, "utf8");
-  await gate.waitForHeldReadyFileUpdate();
-  await expect.poll(() => readFile(filePath, "utf8")).toBe(content);
-}
-
 async function expectOnlyFileCallout(page: Page, title: string): Promise<void> {
   await expect(fileCallout(page)).toHaveCount(1);
   await expect(fileCallout(page)).toContainText(title);
   await expect(filePane(page).getByText(title, { exact: true })).toHaveCount(1);
 }
 
-async function expectCleanReplacementCanReload(page: Page): Promise<void> {
-  await expectOnlyFileCallout(page, "Changed on disk");
-  await expect(filePane(page).getByText("File deleted on disk", { exact: true })).toHaveCount(0);
-  await expect(fileCallout(page).getByRole("button", { name: "Overwrite" })).toHaveCount(0);
-  await expect(fileCallout(page).getByRole("button", { name: "Reload" })).toBeEnabled();
-  await fileCallout(page).getByRole("button", { name: "Reload" }).click();
-  await expect(filePane(page).getByText("After", { exact: true })).toBeVisible();
-  await expect(fileCallout(page)).toHaveCount(0);
-}
-
 async function expectDeletedFileNotice(page: Page): Promise<void> {
   await expectOnlyFileCallout(page, "File deleted on disk");
   await expect(fileCallout(page)).toContainText("The open copy is preserved.");
@@ -140,7 +107,7 @@ test.describe("Workspace file change conflicts", () => {
       relativePath,
       content: "const preserved = true;\n",
     });
-    await gate.waitForFileSubscription(relativePath);
+    await expect(visibleEditor(page)).toContainText("const preserved = true;");
     await recordFileCallouts(page);
 
     await restoreFileAfterWatcherObservedTemporaryAbsence({ gate, filePath, relativePath });
@@ -189,162 +156,79 @@ test.describe("Workspace file change conflicts", () => {
       relativePath,
       content: "const before = true;\n",
     });
-    await gate.waitForFileSubscription(relativePath);
+    await expect(visibleEditor(page)).toContainText("const before = true;");
     await recordFileCallouts(page);
-    gate.holdFileReads(relativePath);
+    gate.holdNextReadyFileUpdate(relativePath);
 
     await replaceEditorText(page, "const saved = true;\n");
     await expect.poll(() => readFile(filePath, "utf8")).toContain("const saved = true;");
-    await gate.waitForHeldFileRead();
+    await gate.waitForHeldReadyFileUpdate();
+    gate.releaseHeldReadyFileUpdate();
 
     await expect(visibleEditor(page)).toContainText("const saved = true;");
     await expect(fileCallout(page)).toHaveCount(0);
     await expectNoFileCalloutWasRendered(page);
-    gate.releaseHeldFileRead();
   });
 
-  test("a clean file replaced on disk offers one working reload action", async ({
+  test("a viewed file deleted and written back shows the new file", async ({
     page,
     withWorkspace,
   }) => {
-    const gate = await installDaemonWebSocketGate(page);
     const filePath = await openTrackedFile(page, withWorkspace, {
       prefix: "file-clean-replacement-",
       relativePath: "inventory.md",
       content: "# Before\n",
     });
     await expect(filePane(page).getByText("Before", { exact: true })).toBeVisible();
-    await replaceFileAfterDeletionWasObserved({
-      page,
-      gate,
-      filePath,
-      relativePath: "inventory.md",
-      content: "# After\n",
-    });
-    gate.releaseHeldReadyFileUpdate();
-    await expectCleanReplacementCanReload(page);
+
+    await unlink(filePath);
+    await expect(filePane(page).getByText("The file was deleted.", { exact: true })).toBeVisible();
+    await writeFile(filePath, "# After\n", "utf8");
+
+    await expect(filePane(page).getByText("After", { exact: true })).toBeVisible();
+    await expect(fileCallout(page)).toHaveCount(0);
   });
 
-  test("a deleted file shows one explanatory notice and no resolution actions", async ({
+  test("a deleted file keeps the open copy with one notice and no resolution actions", async ({
     page,
     withWorkspace,
   }) => {
     const filePath = await openTrackedFile(page, withWorkspace, {
       prefix: "file-deleted-",
-      relativePath: "deleted.md",
-      content: "# Present\n",
+      relativePath: "deleted.ts",
+      content: "const present = true;\n",
     });
-    await expect(filePane(page).getByText("Present", { exact: true })).toBeVisible();
+    await expect(visibleEditor(page)).toContainText("const present = true;");
     await recordFileCallouts(page);
     await unlink(filePath);
     await expectDeletedFileNotice(page);
     await expectFileCalloutWasRendered(page, "File deleted on disk");
+    await expect(visibleEditor(page)).toContainText("const present = true;");
   });
 
-  test("a file check error offers a working retry", async ({ page, withWorkspace }) => {
-    const gate = await installDaemonWebSocketGate(page);
-    const relativePath = "retry.md";
-    const filePath = await openTrackedFile(page, withWorkspace, {
-      prefix: "file-check-retry-",
-      relativePath,
-      content: "# Before\n",
-    });
-    await gate.waitForFileSubscription(relativePath);
-    await expect(filePane(page).getByText("Before", { exact: true })).toBeVisible();
-
-    await unlink(filePath);
-    await mkdir(filePath);
-    await expectOnlyFileCallout(page, "Couldn't check file on disk");
-    await expect(fileCallout(page).getByRole("button", { name: "Retry" })).toBeEnabled();
-    await expect(fileCallout(page).getByRole("button", { name: "Reload" })).toHaveCount(0);
-    await expect(fileCallout(page).getByRole("button", { name: "Overwrite" })).toHaveCount(0);
-
-    gate.holdNextReadyFileUpdate(relativePath);
-    await rm(filePath, { recursive: true });
-    await writeFile(filePath, "# After\n", "utf8");
-    await gate.waitForHeldReadyFileUpdate();
-    gate.holdFileReads(relativePath);
-    await fileCallout(page).getByRole("button", { name: "Retry" }).click();
-    await gate.waitForHeldFileRead();
-    await expect(fileCallout(page).getByRole("button", { name: "Retry" })).toBeDisabled();
-    gate.releaseHeldFileRead();
-    await expectCleanReplacementCanReload(page);
-    gate.releaseHeldReadyFileUpdate();
-  });
-
-  test("retry clears a transient error when the file is unchanged", async ({
+  test("a path that stops being a file keeps the open copy and follows the file back", async ({
     page,
     withWorkspace,
   }) => {
     const gate = await installDaemonWebSocketGate(page);
-    const relativePath = "unchanged.md";
+    const relativePath = "retry.ts";
     const filePath = await openTrackedFile(page, withWorkspace, {
-      prefix: "file-check-unchanged-",
+      prefix: "file-check-error-",
       relativePath,
-      content: "# Unchanged\n",
+      content: "const before = true;\n",
     });
-    const parkedPath = `${filePath}.parked`;
-    await gate.waitForFileSubscription(relativePath);
-    await expect(filePane(page).getByText("Unchanged", { exact: true })).toBeVisible();
+    await expect(visibleEditor(page)).toContainText("const before = true;");
 
-    await rename(filePath, parkedPath);
+    await unlink(filePath);
     await mkdir(filePath);
-    await expectOnlyFileCallout(page, "Couldn't check file on disk");
+    await gate.waitForFileUpdate(relativePath, "error");
+    await expect(visibleEditor(page)).toContainText("const before = true;");
 
-    gate.holdNextReadyFileUpdate(relativePath);
     await rm(filePath, { recursive: true });
-    await rename(parkedPath, filePath);
-    await gate.waitForHeldReadyFileUpdate();
-    await fileCallout(page).getByRole("button", { name: "Retry" }).click();
+    await writeFile(filePath, "const after = true;\n", "utf8");
 
+    await expect(visibleEditor(page)).toContainText("const after = true;");
     await expect(fileCallout(page)).toHaveCount(0);
-    await expect(filePane(page).getByText("Changed on disk", { exact: true })).toHaveCount(0);
-    gate.releaseHeldReadyFileUpdate();
-  });
-
-  test("a read-only file error preserves its message and offers retry", async ({
-    page,
-    withWorkspace,
-  }) => {
-    const gate = await installDaemonWebSocketGate(page);
-    const relativePath = "artifact.bin";
-    const binaryContent = new Uint8Array([0, 1, 2, 3, 255]);
-    const filePath = await openTrackedFile(page, withWorkspace, {
-      prefix: "file-read-only-retry-",
-      relativePath,
-      content: binaryContent,
-    });
-    await gate.waitForFileSubscription(relativePath);
-    await expect(
-      filePane(page).getByText("Binary preview unavailable", { exact: true }),
-    ).toBeVisible();
-
-    await unlink(filePath);
-    await mkdir(filePath);
-    await expect(
-      filePane(page).getByText("Requested path is not a file", { exact: true }),
-    ).toBeVisible();
-    await expect(filePane(page).getByRole("button", { name: "Retry" })).toBeEnabled();
-
-    gate.holdNextReadyFileUpdate(relativePath);
-    await rm(filePath, { recursive: true });
-    await writeFile(filePath, binaryContent);
-    await gate.waitForHeldReadyFileUpdate();
-    gate.holdFileReads(relativePath);
-    await filePane(page).getByRole("button", { name: "Retry" }).click();
-    await gate.waitForHeldFileRead();
-    await expect(
-      filePane(page).getByText("Requested path is not a file", { exact: true }),
-    ).toHaveCount(0);
-    gate.releaseHeldFileRead();
-
-    await expect(
-      filePane(page).getByText("Binary preview unavailable", { exact: true }),
-    ).toBeVisible();
-    await expect(
-      filePane(page).getByText("Requested path is not a file", { exact: true }),
-    ).toHaveCount(0);
-    gate.releaseHeldReadyFileUpdate();
   });
 
   test("a changed file with local edits offers overwrite and a working reload", async ({

packages/app/e2e/browser/file-editing.spec.ts

@@ -55,6 +55,10 @@ async function openWorkspaceFile(page: Page, filename: string): Promise<void> {
   await expectFileTabOpen(page, filename);
 }
 
+function filePanelSwitcher(page: Page) {
+  return page.getByTestId("file-panel-switcher").filter({ visible: true });
+}
+
 function htmlPreview(page: Page) {
   return {
     host: page.getByTestId("file-html-preview"),
@@ -62,11 +66,9 @@ function htmlPreview(page: Page) {
   };
 }
 
-async function selectFileView(page: Page, view: "Preview" | "Source"): Promise<void> {
-  const option = page.getByTestId("file-panel-bar").getByRole("button", {
-    name: view,
-    exact: true,
-  });
+/** Switches the file tab to one of its panels from the bar's switcher. */
+async function selectFilePanel(page: Page, title: string): Promise<void> {
+  const option = filePanelSwitcher(page).getByRole("button", { name: title, exact: true });
   await option.click();
   await expect(option).toHaveAttribute("aria-selected", "true");
 }
@@ -128,7 +130,7 @@ test.describe("CodeMirror workspace file editing", () => {
         await returnToAssistant(page, session.agentId);
         await openAssistantMarkdownLink(page, "Missing capture");
         await expectFileTabOpen(page, ".dev/tablet-review/missing.png");
-        await expect(page.getByText(/ENOENT/)).toBeVisible();
+        await expect(page.getByText("File not found", { exact: true })).toBeVisible();
         await expect(page.getByRole("button", { name: "Retry", exact: true })).toBeVisible();
       });
     } finally {
@@ -317,11 +319,7 @@ test.describe("CodeMirror workspace file editing", () => {
       title: "Unsupported large source",
       initialPrompt: "Generate a title and a git branch name. Return JSON only.",
     });
-    await writeFile(
-      path.join(session.cwd, "too-large.txt"),
-      Buffer.alloc(51 * 1024 * 1024),
-      "utf8",
-    );
+    await writeFile(path.join(session.cwd, "too-large.txt"), "x".repeat(51 * 1024 * 1024), "utf8");
 
     try {
       await openAgentRoute(page, session);
@@ -484,9 +482,9 @@ test.describe("CodeMirror workspace file editing", () => {
       relativePath,
     );
     await expect(page.getByTestId("file-panel-bar")).not.toContainText("visuals.md");
-    const modeControl = page.getByTestId("file-preview-mode");
+    const modeControl = filePanelSwitcher(page);
     await expect(modeControl).toBeVisible();
-    await selectFileView(page, "Source");
+    await selectFilePanel(page, "Source");
 
     const editorHost = page.getByTestId("file-source-editor");
     const content = editor(page);
@@ -548,7 +546,7 @@ test.describe("CodeMirror workspace file editing", () => {
     );
     await workspace.navigateTo();
     await openWorkspaceFile(page, "notes.md");
-    await selectFileView(page, "Source");
+    await selectFilePanel(page, "Source");
 
     const markdownScroller = page
       .getByTestId("file-source-editor")
@@ -680,7 +678,7 @@ test.describe("CodeMirror workspace file editing", () => {
     await expect(page.getByTestId("workspace-tab-modified-file_draft.ts")).toBeVisible();
   });
 
-  test("refreshes Markdown and images while preserving Preview and Source behavior", async ({
+  test("refreshes Markdown and images while switching between Markdown and Source", async ({
     page,
     withWorkspace,
   }) => {
@@ -695,15 +693,15 @@ test.describe("CodeMirror workspace file editing", () => {
 
     const visibleFilePane = page.getByTestId("workspace-file-pane").filter({ visible: true });
     await expect(visibleFilePane.getByText("First heading", { exact: true })).toBeVisible();
-    await expect(page.getByRole("button", { name: "Preview", exact: true })).toBeVisible();
+    await expect(filePanelSwitcher(page).getByRole("button", { name: "Markdown" })).toBeVisible();
     await writeFile(markdownPath, "# Updated heading\n", "utf8");
     await expect(visibleFilePane.getByText("Updated heading", { exact: true })).toBeVisible();
 
-    await selectFileView(page, "Source");
+    await selectFilePanel(page, "Source");
     await expect(page.getByTestId("file-source-editor")).toBeVisible();
     await replaceEditorText(page, "# Saved from source\n");
     await expect.poll(() => readFile(markdownPath, "utf8")).toBe("# Saved from source\n");
-    await selectFileView(page, "Preview");
+    await selectFilePanel(page, "Markdown");
     await expect(visibleFilePane.getByText("Saved from source", { exact: true })).toBeVisible();
 
     await openWorkspaceFile(page, "pixel.png");
@@ -786,10 +784,10 @@ test.describe("CodeMirror workspace file editing", () => {
     );
     await expect(preview.document.getByRole("heading", { name: "Updated plan" })).toBeVisible();
 
-    await selectFileView(page, "Source");
+    await selectFilePanel(page, "Source");
     await expect(page.getByTestId("file-source-editor")).toBeVisible();
     await expect(preview.host).toHaveCount(0);
-    await selectFileView(page, "Preview");
+    await selectFilePanel(page, "HTML");
     await expect(preview.host).toBeVisible();
   });
 

packages/app/e2e/browser/folder-links.spec.ts

@@ -14,8 +14,9 @@ async function openMarkdownPreview(page: Page) {
   await openFileFromExplorer(page, "README.md");
   await expectFileTabOpen(page, "README.md");
   await page
-    .getByTestId("file-panel-bar")
-    .getByRole("button", { name: "Preview", exact: true })
+    .getByTestId("file-panel-switcher")
+    .filter({ visible: true })
+    .getByRole("button", { name: "Markdown", exact: true })
     .click();
   await ensureWorkspaceAgentPaneVisible(page);
 }

packages/app/e2e/browser/new-workspace-launch-terminal.spec.ts

@@ -247,9 +247,7 @@ test.describe("New workspace: fullscreen composer across the compact breakpoint"
       await expectNewWorkspaceDraft(page, `${draft} wide`);
     });
 
-    // Terminal mode and its prompt are screen state, and the shell remounts the screen
-    // at the breakpoint, so the terminal prompt's fullscreen is exercised on the phone
-    // layout only.
+    // Exercise the terminal prompt's fullscreen and compact launch sheet on the phone.
     await test.step("terminal: the prompt's fullscreen shows only exit and Launch", async () => {
       await resizeComposerViewport(page, "portrait");
       // The compact launch control opens a sheet, not the desktop menu.

packages/app/e2e/browser/plugin-file-panel-examples.spec.ts

@@ -0,0 +1,272 @@
+import { execFileSync } from "node:child_process";
+import { readFile, writeFile } from "node:fs/promises";
+import path from "node:path";
+import type { Frame, TestInfo } from "@playwright/test";
+import { expect, test, type Page } from "../support/fixtures";
+import { copyPluginExample } from "../support/helpers/plugin-fixture";
+import { connectNewWorkspaceDaemonClient } from "../support/helpers/new-workspace";
+import { seedWorkspace } from "../support/helpers/seed-client";
+import { gotoWorkspace } from "../support/helpers/launcher";
+import { installDaemonWebSocketGate } from "../support/helpers/daemon-websocket-gate";
+import {
+  openFileExplorer,
+  openFileFromExplorer,
+  expectFileTabOpen,
+} from "../support/helpers/file-explorer";
+
+// Full Chromium includes the PDF viewer; the default headless shell does not.
+test.use({ channel: "chromium" });
+
+function samplePdf() {
+  const stream = "BT /F1 24 Tf 72 720 Td (Paseo PDF panel example) Tj ET";
+  const objects = [
+    "<< /Type /Catalog /Pages 2 0 R >>",
+    "<< /Type /Pages /Kids [3 0 R] /Count 1 >>",
+    "<< /Type /Page /Parent 2 0 R /MediaBox [0 0 612 792] /Resources << /Font << /F1 4 0 R >> >> /Contents 5 0 R >>",
+    "<< /Type /Font /Subtype /Type1 /BaseFont /Helvetica >>",
+    `<< /Length ${stream.length} >>\nstream\n${stream}\nendstream`,
+  ];
+  let pdf = "%PDF-1.4\n%\u0000\u00ff\n";
+  const offsets = objects.map((object, index) => {
+    const offset = Buffer.byteLength(pdf);
+    pdf += `${index + 1} 0 obj\n${object}\nendobj\n`;
+    return offset;
+  });
+  const xref = Buffer.byteLength(pdf);
+  pdf += `xref\n0 6\n0000000000 65535 f \n${offsets.map((offset) => `${String(offset).padStart(10, "0")} 00000 n \n`).join("")}`;
+  pdf += `trailer\n<< /Size 6 /Root 1 0 R >>\nstartxref\n${xref}\n%%EOF\n`;
+  return pdf;
+}
+
+async function openFile(page: Page, name: string) {
+  await openFileFromExplorer(page, name);
+  await expectFileTabOpen(page, name);
+}
+
+const WIDE = { width: 1280, height: 900 };
+const COMPACT = { width: 390, height: 844 };
+
+async function capture(page: Page, testInfo: TestInfo, name: string) {
+  const file = testInfo.outputPath(`${name}.png`);
+  await page.screenshot({ path: file });
+  await testInfo.attach(name, { path: file, contentType: "image/png" });
+}
+
+/** Captures the current state wide, then compact once `ready` holds there, and returns to wide. */
+async function captureWideAndCompact(
+  page: Page,
+  testInfo: TestInfo,
+  name: string,
+  ready: () => Promise<void>,
+) {
+  await capture(page, testInfo, `${name}-wide`);
+  await page.setViewportSize(COMPACT);
+  await ready();
+  await capture(page, testInfo, `${name}-compact`);
+  await page.setViewportSize(WIDE);
+  await ready();
+}
+
+function filePanelSwitcher(page: Page) {
+  return page.getByTestId("file-panel-switcher").filter({ visible: true });
+}
+
+/** Turns on vim keybindings without discarding settings the test writes later. */
+async function enableVimKeybindings(page: Page) {
+  await page.addInitScript(() => {
+    const key = "@paseo:app-settings";
+    const settings = JSON.parse(localStorage.getItem(key) ?? "{}");
+    localStorage.setItem(key, JSON.stringify({ ...settings, vimKeybindings: true }));
+  });
+}
+
+async function chooseRichMarkdown(page: Page) {
+  await page.getByRole("radio", { name: "Rich Markdown — markdown-panel", exact: true }).click();
+  await page.getByRole("checkbox", { name: "Don't ask me again", exact: true }).click();
+  await page.getByRole("button", { name: "Use", exact: true }).click();
+}
+
+async function replaceMarkdown(page: Page, text: string) {
+  await page.getByRole("textbox", { name: "Rich Markdown editor", exact: true }).fill(text);
+}
+
+async function selectPanel(page: Page, title: string) {
+  await filePanelSwitcher(page).getByRole("button", { name: title, exact: true }).click();
+}
+
+async function expectPanels(page: Page, titles: string[]) {
+  for (const title of titles) {
+    await expect(
+      filePanelSwitcher(page).getByRole("button", { name: title, exact: true }),
+    ).toBeInViewport({ ratio: 1 });
+  }
+}
+
+/** The browser's PDF viewer in the mounted frame; a remounted pane leaves old frames detached. */
+async function pdfViewer(page: Page): Promise<Frame> {
+  const viewerUrl = /^chrome-extension:\/\/[^/]+\/index\.html$/;
+  const find = () =>
+    page.frames().find((frame) => !frame.isDetached() && viewerUrl.test(frame.url())) ?? null;
+  await expect.poll(() => find() !== null).toBe(true);
+  return find()!;
+}
+
+async function expectPdfViewerReady(page: Page) {
+  // A narrow viewer collapses its toolbar to Print and More actions.
+  const viewer = await pdfViewer(page);
+  await expect(viewer.getByRole("button", { name: "Print", exact: true })).toBeEnabled();
+}
+
+async function expectMarkdownEditor(page: Page, text: string) {
+  const editor = page.getByRole("textbox", { name: "Rich Markdown editor", exact: true });
+  await expect(editor).toBeVisible();
+  await expect(editor).toContainText(text);
+  await expect(editor).toBeInViewport({ ratio: 1 });
+  // Side by side on a wide screen; on a phone three panels do not fit, so the switcher is a menu.
+  await expect(filePanelSwitcher(page)).toContainText("Rich Markdown");
+  await expect(filePanelSwitcher(page)).toBeInViewport({ ratio: 1 });
+}
+
+test("directory examples mount the PDF frame and write Markdown through the file handle", async ({
+  page,
+}, testInfo) => {
+  test.setTimeout(180_000);
+  const pdf = await copyPluginExample("pdf-panel");
+  const markdown = await copyPluginExample("markdown-panel");
+  execFileSync(
+    process.platform === "win32" ? "npm.cmd" : "npm",
+    ["install", "--ignore-scripts", "--no-audit", "--no-fund"],
+    { cwd: markdown.directory, stdio: "pipe" },
+  );
+  const workspace = await seedWorkspace({
+    repoPrefix: "file-panel-examples-",
+    repo: {
+      files: [
+        {
+          path: "notes.md",
+          content: "# Markdown panel example\n\nEdit **Markdown** through Paseo.\n",
+        },
+        { path: "second.md", content: "# Remembered panel\n" },
+        { path: "report.pdf", content: samplePdf() },
+      ],
+    },
+  });
+  const client = await connectNewWorkspaceDaemonClient({ ownProjects: false });
+  const previous = await client.getDaemonConfig();
+  try {
+    await client.patchDaemonConfig({ pluginsEnabled: true });
+    await client.installDirectoryPlugin(pdf.directory);
+    await client.installDirectoryPlugin(markdown.directory);
+    await enableVimKeybindings(page);
+    await page.setViewportSize(WIDE);
+    const gate = await installDaemonWebSocketGate(page);
+    await gotoWorkspace(page, workspace.workspaceId);
+    await openFileExplorer(page);
+    await openFile(page, "report.pdf");
+    await expect(page.getByTitle("Document preview", { exact: true })).toHaveAttribute(
+      "src",
+      /^blob:/,
+    );
+    await expect(page.getByTitle("Document preview", { exact: true })).not.toHaveAttribute(
+      "sandbox",
+    );
+    const documentUrl = await page
+      .getByTitle("Document preview", { exact: true })
+      .getAttribute("src");
+    expect(
+      await page.evaluate(
+        async (url) => (await fetch(url!)).blob().then((blob) => blob.type),
+        documentUrl,
+      ),
+    ).toBe("application/pdf");
+    await expectPdfViewerReady(page);
+    await expect(
+      (await pdfViewer(page)).getByRole("textbox", { name: "Page number", exact: true }),
+    ).toHaveValue("1");
+    await captureWideAndCompact(page, testInfo, "pdf-example", async () => {
+      await expect(page.getByTitle("Document preview", { exact: true })).toBeInViewport();
+      await expectPdfViewerReady(page);
+    });
+
+    await openFile(page, "notes.md");
+    await expect(page.getByRole("radio", { name: "Markdown — Paseo", exact: true })).toBeChecked();
+    await expect(
+      page.getByRole("radio", { name: "Rich Markdown — markdown-panel", exact: true }),
+    ).toBeVisible();
+    await expect(page.getByRole("radio", { name: "Source — Paseo", exact: true })).toBeVisible();
+    await captureWideAndCompact(page, testInfo, "markdown-example-picker", async () => {
+      await expect(page.getByRole("button", { name: "Use", exact: true })).toBeInViewport({
+        ratio: 1,
+      });
+    });
+    await chooseRichMarkdown(page);
+    await expect(page.getByRole("textbox", { name: "Rich Markdown editor" })).toContainText(
+      "Markdown panel example",
+    );
+    gate.holdNextClientRequest("fs.file.write.request");
+    await replaceMarkdown(page, "# Edited by Rich Markdown\n\nSaved by the panel.\n");
+    await gate.waitForHeldClientRequest();
+    await expect(page.getByTestId("workspace-tab-modified-file_notes.md")).toBeVisible();
+    await capture(page, testInfo, "markdown-example-dirty-wide");
+    gate.releaseHeldClientRequest();
+    await expect
+      .poll(() => readFile(path.join(workspace.repoPath, "notes.md"), "utf8"))
+      .toBe("# Edited by Rich Markdown\n\nSaved by the panel.\n");
+    await expect(page.getByTestId("workspace-tab-modified-file_notes.md")).toBeHidden();
+    await expectPanels(page, ["Rich Markdown", "Markdown", "Source"]);
+    await captureWideAndCompact(page, testInfo, "markdown-example-rich-markdown", async () => {
+      await expectMarkdownEditor(page, "Edited by Rich Markdown");
+    });
+
+    // Source is Paseo's editor; its cursor and vim mode are in its own status row.
+    await selectPanel(page, "Source");
+    const source = page.getByTestId("file-source-editor").filter({ visible: true });
+    await expect(source.locator(".cm-content")).toContainText("Edited by Rich Markdown");
+    await source.locator(".cm-line").nth(2).click();
+    const bar = page.getByTestId("file-source-status").filter({ visible: true });
+    await expect(bar.getByText("NORMAL", { exact: true })).toBeVisible();
+    await expect(bar.getByText(/^Ln 3, Col \d+$/)).toBeVisible();
+    await capture(page, testInfo, "markdown-example-source-wide");
+    // The phone layout mounts the tab anew, so it opens the remembered panel; its menu offers Source.
+    await page.setViewportSize(COMPACT);
+    await expect(filePanelSwitcher(page)).toHaveText("Rich Markdown");
+    await filePanelSwitcher(page).click();
+    await page.getByRole("menuitem", { name: "Source", exact: true }).click();
+    await expect(filePanelSwitcher(page)).toHaveText("Source");
+    await source.locator(".cm-line").nth(2).click();
+    await expect(bar.getByText("NORMAL", { exact: true })).toBeInViewport();
+    await expect(bar.getByText(/^Ln 3, Col \d+$/)).toBeInViewport();
+    await capture(page, testInfo, "markdown-example-source-compact");
+    await page.setViewportSize(WIDE);
+    await selectPanel(page, "Rich Markdown");
+    await writeFile(path.join(workspace.repoPath, "notes.md"), "# External update\n");
+    await expect(page.getByRole("textbox", { name: "Rich Markdown editor" })).toHaveText(
+      "# External update",
+    );
+    await replaceMarkdown(page, "# Local edit\n");
+    await writeFile(path.join(workspace.repoPath, "notes.md"), "# Conflicting external edit\n");
+    await expect(page.getByTestId("rich-markdown-conflict")).toBeVisible();
+    await capture(page, testInfo, "markdown-example-conflict-wide");
+    await page.getByRole("button", { name: "Overwrite", exact: true }).click();
+    await expect
+      .poll(() => readFile(path.join(workspace.repoPath, "notes.md"), "utf8"))
+      .toBe("# Local edit\n");
+
+    await openFile(page, "second.md");
+    await expect(page.getByRole("textbox", { name: "Rich Markdown editor" })).toContainText(
+      "Remembered panel",
+    );
+    await expect(page.getByText("Open .md files with", { exact: true })).toBeHidden();
+    await page.setViewportSize(COMPACT);
+    await expectMarkdownEditor(page, "Remembered panel");
+    await expect(filePanelSwitcher(page)).toHaveText("Rich Markdown");
+  } finally {
+    await client.removePlugin("pdf-panel");
+    await client.removePlugin("markdown-panel");
+    await client.patchDaemonConfig({ pluginsEnabled: previous.config.pluginsEnabled ?? false });
+    await client.close();
+    await workspace.cleanup();
+    await pdf.cleanup();
+    await markdown.cleanup();
+  }
+});

packages/app/e2e/browser/plugin-file-panel-picker.spec.ts

@@ -0,0 +1,156 @@
+import type { TestInfo } from "@playwright/test";
+import { expect, test, type Page } from "../support/fixtures";
+import { seedWorkspace } from "../support/helpers/seed-client";
+import { gotoWorkspace } from "../support/helpers/launcher";
+import { expectFileTabOpen, openFileExplorer } from "../support/helpers/file-explorer";
+import {
+  BUILTIN_MARKDOWN_OPTION,
+  MARKDOWN_PANEL_ID,
+  PLUGIN_MARKDOWN_OPTION,
+  expectBuiltinMarkdown,
+  expectPluginMarkdown,
+  filePanelPicker,
+  installMarkdownPanelPlugin,
+  openMarkdown,
+  storedFilePanelAssociations,
+} from "../support/helpers/markdown-file-panel-plugin";
+
+async function choosePanel(page: Page, option: string, options: { remember: boolean }) {
+  await page.getByRole("radio", { name: option, exact: true }).click();
+  if (options.remember) {
+    await page.getByRole("checkbox", { name: "Don't ask me again", exact: true }).click();
+  }
+  await page.getByRole("button", { name: "Use", exact: true }).click();
+  await expect(filePanelPicker(page)).toBeHidden();
+}
+
+async function openWithFromTabMenu(page: Page, name: string, option: string) {
+  await page.getByTestId(`workspace-tab-file_${name}`).first().click({ button: "right" });
+  await page.getByRole("menuitem", { name: "Open with…" }).hover();
+  await page.getByRole("menuitem", { name: option }).click();
+}
+
+async function toggleAlwaysUseFromFileBar(page: Page) {
+  await page.getByTestId("file-panel-bar-menu").filter({ visible: true }).click();
+  await page.getByRole("menuitem", { name: "Always use for .md" }).click();
+}
+
+function filePanelSwitcher(page: Page) {
+  return page.getByTestId("file-panel-switcher").filter({ visible: true });
+}
+
+async function expectSwitcherPanels(page: Page, titles: string[]) {
+  await expect(filePanelSwitcher(page).getByRole("button")).toHaveText(titles);
+}
+
+async function capture(page: Page, testInfo: TestInfo, name: string) {
+  const file = testInfo.outputPath(`${name}.png`);
+  await page.screenshot({ path: file });
+  await testInfo.attach(name, { path: file, contentType: "image/png" });
+}
+
+test("opens Markdown with the built-in panel and Source beside it without asking", async ({
+  page,
+}, testInfo) => {
+  const workspace = await seedWorkspace({
+    repoPrefix: "file-panel-builtins-",
+    repo: { files: [{ path: "notes.md", content: "# notes heading\n" }] },
+  });
+  try {
+    await page.setViewportSize({ width: 1280, height: 900 });
+    await gotoWorkspace(page, workspace.workspaceId);
+    await openFileExplorer(page);
+    await openMarkdown(page, "notes.md");
+    await expectBuiltinMarkdown(page, "notes heading");
+    await expectSwitcherPanels(page, ["Markdown", "Source"]);
+    await expect(filePanelPicker(page)).toBeHidden();
+    await capture(page, testInfo, "file-panel-builtins-wide");
+
+    await filePanelSwitcher(page).getByRole("button", { name: "Source", exact: true }).click();
+    await expect(page.getByTestId("file-source-editor").filter({ visible: true })).toBeVisible();
+    await filePanelSwitcher(page).getByRole("button", { name: "Markdown", exact: true }).click();
+    await expectBuiltinMarkdown(page, "notes heading");
+
+    await page.setViewportSize({ width: 390, height: 844 });
+    await expectBuiltinMarkdown(page, "notes heading");
+    await expect(
+      filePanelSwitcher(page).getByRole("button", { name: "Source", exact: true }),
+    ).toBeInViewport({ ratio: 1 });
+    await expect(filePanelPicker(page)).toBeHidden();
+    await capture(page, testInfo, "file-panel-builtins-compact");
+  } finally {
+    await workspace.cleanup();
+  }
+});
+
+test("asks once which panel opens Markdown and remembers it when told to", async ({
+  page,
+}, testInfo) => {
+  test.setTimeout(120_000);
+  const workspace = await seedWorkspace({
+    repoPrefix: "file-panel-picker-",
+    repo: {
+      files: ["first", "second", "third", "fourth"].map((name) => ({
+        path: `${name}.md`,
+        content: `# ${name} heading\n`,
+      })),
+    },
+  });
+  const plugin = await installMarkdownPanelPlugin();
+  try {
+    await page.setViewportSize({ width: 1280, height: 900 });
+    await gotoWorkspace(page, workspace.workspaceId);
+    await openFileExplorer(page);
+
+    // First open: the built-in renders under the picker.
+    await openMarkdown(page, "first.md");
+    await expect(filePanelPicker(page)).toBeVisible();
+    await expect(page.getByRole("radio", { name: BUILTIN_MARKDOWN_OPTION })).toBeChecked();
+    await expect(page.getByRole("radio", { name: PLUGIN_MARKDOWN_OPTION })).not.toBeChecked();
+    await expectBuiltinMarkdown(page, "first heading");
+    await capture(page, testInfo, "file-panel-picker-wide");
+
+    // Don't ask me again: the plugin renders and later opens use it silently.
+    await choosePanel(page, PLUGIN_MARKDOWN_OPTION, { remember: true });
+    await expectPluginMarkdown(page, "first.md");
+    expect(await storedFilePanelAssociations(page)).toEqual({ "ext:md": MARKDOWN_PANEL_ID });
+    await openMarkdown(page, "second.md");
+    await expectPluginMarkdown(page, "second.md");
+    await expect(filePanelPicker(page)).toBeHidden();
+
+    // Forgetting from the file bar keeps the tab on the plugin.
+    await toggleAlwaysUseFromFileBar(page);
+    await expect.poll(() => storedFilePanelAssociations(page)).toEqual({});
+    await expectPluginMarkdown(page, "second.md");
+
+    // An unremembered choice applies to this tab only; the next open asks again.
+    await openMarkdown(page, "third.md");
+    await expect(filePanelPicker(page)).toBeVisible();
+    await choosePanel(page, PLUGIN_MARKDOWN_OPTION, { remember: false });
+    await expectPluginMarkdown(page, "third.md");
+    expect(await storedFilePanelAssociations(page)).toEqual({});
+
+    // "Open with…" switches the open tab back to the built-in in place.
+    await openWithFromTabMenu(page, "third.md", BUILTIN_MARKDOWN_OPTION);
+    await expectBuiltinMarkdown(page, "third heading");
+    await expectFileTabOpen(page, "third.md");
+
+    // Dismissing keeps the built-in; reopening the tab after a reload asks again.
+    await openMarkdown(page, "fourth.md");
+    await expect(filePanelPicker(page)).toBeVisible();
+    await page.keyboard.press("Escape");
+    await expect(filePanelPicker(page)).toBeHidden();
+    await expectBuiltinMarkdown(page, "fourth heading");
+
+    await page.setViewportSize({ width: 390, height: 844 });
+    await page.reload();
+    await expect(filePanelPicker(page)).toBeVisible({ timeout: 30_000 });
+    await expect(page.getByRole("button", { name: "Use", exact: true })).toBeInViewport({
+      ratio: 1,
+    });
+    await capture(page, testInfo, "file-panel-picker-compact");
+  } finally {
+    await plugin.uninstall();
+    await workspace.cleanup();
+  }
+});

packages/app/e2e/browser/plugin-file-panel-settings.spec.ts

@@ -0,0 +1,150 @@
+import type { TestInfo } from "@playwright/test";
+import { expect, test, type Page } from "../support/fixtures";
+import { openSettings } from "../support/helpers/app";
+import { openFileExplorer } from "../support/helpers/file-explorer";
+import { gotoWorkspace } from "../support/helpers/launcher";
+import {
+  BUILTIN_MARKDOWN_OPTION,
+  MARKDOWN_PANEL_ID,
+  PLUGIN_MARKDOWN_OPTION,
+  SOURCE_OPTION,
+  expectPluginMarkdown,
+  filePanelPicker,
+  installMarkdownPanelPlugin,
+  openMarkdown,
+  storedFilePanelAssociations,
+} from "../support/helpers/markdown-file-panel-plugin";
+import { seedWorkspace } from "../support/helpers/seed-client";
+import { openSettingsSection } from "../support/helpers/settings";
+
+const ASK_EVERY_TIME = "Ask every time";
+
+function markdownRow(page: Page) {
+  return page.getByTestId("file-panel-settings-row-ext:md");
+}
+
+function markdownDropdown(page: Page, value: string) {
+  return markdownRow(page).getByRole("button", { name: `.md: ${value}`, exact: true });
+}
+
+function askAgain(page: Page) {
+  return markdownRow(page).getByRole("button", { name: "Ask again for .md", exact: true });
+}
+
+async function openFilesSettings(page: Page) {
+  await openSettings(page);
+  await openSettingsSection(page, "files");
+  await expect(page.getByTestId("file-panel-settings")).toBeVisible();
+}
+
+async function capture(page: Page, testInfo: TestInfo, name: string) {
+  const file = testInfo.outputPath(`${name}.png`);
+  await page.screenshot({ path: file });
+  await testInfo.attach(name, { path: file, contentType: "image/png" });
+}
+
+async function expectMenuOpen(page: Page) {
+  await expect(page.getByTestId("file-panel-settings-menu")).toHaveCSS("opacity", "1");
+}
+
+test("Settings > Files chooses which panel opens .md and asks again on request", async ({
+  page,
+}, testInfo) => {
+  test.setTimeout(120_000);
+  const workspace = await seedWorkspace({
+    repoPrefix: "file-panel-settings-",
+    repo: { files: [{ path: "notes.md", content: "# notes heading\n" }] },
+  });
+  const plugin = await installMarkdownPanelPlugin();
+  try {
+    await page.setViewportSize({ width: 1280, height: 900 });
+    await gotoWorkspace(page, workspace.workspaceId);
+    await openFilesSettings(page);
+
+    // Nothing remembered: the row asks every time and has nothing to forget.
+    await expect(markdownDropdown(page, ASK_EVERY_TIME)).toBeVisible({ timeout: 30_000 });
+    await expect(askAgain(page)).toBeDisabled();
+    await capture(page, testInfo, "file-panel-settings-wide");
+
+    await markdownDropdown(page, ASK_EVERY_TIME).click();
+    await expect(page.getByRole("menuitem", { name: BUILTIN_MARKDOWN_OPTION })).toBeVisible();
+    await expect(page.getByRole("menuitem", { name: PLUGIN_MARKDOWN_OPTION })).toBeVisible();
+    await expect(page.getByRole("menuitem", { name: SOURCE_OPTION })).toBeVisible();
+    await expectMenuOpen(page);
+    await capture(page, testInfo, "file-panel-settings-wide-menu");
+    await page.getByRole("menuitem", { name: PLUGIN_MARKDOWN_OPTION }).click();
+    await expect(markdownDropdown(page, PLUGIN_MARKDOWN_OPTION)).toBeVisible();
+    await expect
+      .poll(() => storedFilePanelAssociations(page))
+      .toEqual({
+        "ext:md": MARKDOWN_PANEL_ID,
+      });
+    await capture(page, testInfo, "file-panel-settings-wide-chosen");
+
+    // The next open uses the plugin without asking.
+    await gotoWorkspace(page, workspace.workspaceId);
+    await openFileExplorer(page);
+    await openMarkdown(page, "notes.md");
+    await expectPluginMarkdown(page, "notes.md");
+    await expect(filePanelPicker(page)).toBeHidden();
+
+    await page.setViewportSize({ width: 390, height: 844 });
+    await page.goto("/settings/files");
+    await expect(markdownDropdown(page, PLUGIN_MARKDOWN_OPTION)).toBeVisible({ timeout: 30_000 });
+    await expect(askAgain(page)).toBeInViewport({ ratio: 1 });
+    await capture(page, testInfo, "file-panel-settings-compact");
+    await markdownDropdown(page, PLUGIN_MARKDOWN_OPTION).click();
+    await expect(page.getByRole("menuitem", { name: SOURCE_OPTION })).toBeVisible();
+    await expectMenuOpen(page);
+    await capture(page, testInfo, "file-panel-settings-compact-menu");
+    await page.keyboard.press("Escape");
+    await expect(page.getByRole("menuitem", { name: SOURCE_OPTION })).toBeHidden();
+
+    // Ask again forgets the choice; the next open asks.
+    await askAgain(page).click();
+    await expect(markdownDropdown(page, ASK_EVERY_TIME)).toBeVisible();
+    await expect.poll(() => storedFilePanelAssociations(page)).toEqual({});
+    await page.setViewportSize({ width: 1280, height: 900 });
+    await gotoWorkspace(page, workspace.workspaceId);
+    await expect(filePanelPicker(page)).toBeVisible({ timeout: 30_000 });
+  } finally {
+    await plugin.uninstall();
+    await workspace.cleanup();
+  }
+});
+
+test("Settings > Files explains where file panels come from when no plugin adds one", async ({
+  page,
+}, testInfo) => {
+  await page.setViewportSize({ width: 1280, height: 900 });
+  await page.goto("/settings/files");
+  const empty = page.getByTestId("file-panel-settings-empty");
+  await expect(empty).toHaveText("File panels appear here when a plugin adds one", {
+    timeout: 30_000,
+  });
+  await capture(page, testInfo, "file-panel-settings-empty-wide");
+  await page.setViewportSize({ width: 390, height: 844 });
+  await expect(empty).toBeVisible();
+  await capture(page, testInfo, "file-panel-settings-empty-compact");
+});
+
+test("Settings > Files offers Source in place of a panel no host has, and forgets it", async ({
+  page,
+}) => {
+  await page.addInitScript(() => {
+    localStorage.setItem(
+      "@paseo:app-settings",
+      JSON.stringify({ filePanelAssociations: { "ext:pdf": "plugin:none/none" } }),
+    );
+  });
+  await page.goto("/settings/files");
+  const row = page.getByTestId("file-panel-settings-row-ext:pdf");
+  const dropdown = row.getByRole("button", { name: ".pdf: Not on a connected host" });
+  await expect(dropdown).toBeEnabled({ timeout: 30_000 });
+  await dropdown.click();
+  await expect(page.getByRole("menuitem", { name: SOURCE_OPTION })).toBeVisible();
+  await page.keyboard.press("Escape");
+  await expect(page.getByRole("menuitem", { name: SOURCE_OPTION })).toBeHidden();
+  await row.getByRole("button", { name: "Ask again for .pdf", exact: true }).click();
+  await expect(page.getByTestId("file-panel-settings-empty")).toBeVisible();
+});

packages/app/e2e/browser/plugin-file-panels.spec.ts

@@ -0,0 +1,232 @@
+import { mkdtemp, readFile, rm, writeFile } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import path from "node:path";
+import { expect, test, type Page } from "../support/fixtures";
+import { installDaemonWebSocketGate } from "../support/helpers/daemon-websocket-gate";
+import { pluginRequirements } from "../support/helpers/plugin-fixture";
+import { connectNewWorkspaceDaemonClient } from "../support/helpers/new-workspace";
+import { seedWorkspace } from "../support/helpers/seed-client";
+import { gotoWorkspace } from "../support/helpers/launcher";
+import {
+  openFileExplorer,
+  openFileFromExplorer,
+  expectFileTabOpen,
+} from "../support/helpers/file-explorer";
+
+const PLUGIN_ID = "file-panel-e2e";
+const PDF = Buffer.from("%PDF-1.4\n%\x00\xff\n1 0 obj<</Type/Catalog>>endobj\n%%EOF", "binary");
+const SOURCE = `import React, { useEffect, useState } from "react";
+import { Text, View, Pressable } from "react-native";
+import {
+  PluginFileConflictError,
+  useFileBytes,
+  useFileUrl,
+  usePaseo,
+  useWorkspace,
+} from "@getpaseo/plugin/client";
+import { useQueryClient } from "@tanstack/react-query";
+import { DocumentFrame, Loading } from "@getpaseo/plugin/client/ui";
+function Pdf({ file, workspaceId }) {
+  usePaseo();
+  useQueryClient();
+  const workspace = useWorkspace(workspaceId, value => ({ id: value.id }));
+  const bytes = useFileBytes(file);
+  const url = useFileUrl(file);
+  const [urlBytes, setUrlBytes] = useState(-1);
+  const href = url.status === "ready" ? url.url : null;
+  useEffect(() => {
+    if (href) fetch(href).then(response => response.arrayBuffer()).then(body => setUrlBytes(body.byteLength));
+  }, [href]);
+  if (bytes.status !== "ready" || !href) return <Loading />;
+  return <View style={{ flex: 1 }}>
+    <Text>PDF plugin: {file.name}</Text>
+    <Text>Path {file.path}</Text>
+    <Text>Bytes {bytes.bytes.length}; URL bytes {urlBytes}</Text>
+    <Text>Workspace {workspace?.id}</Text>
+    <DocumentFrame url={href} testID="plugin-pdf-frame" />
+  </View>;
+}
+// Reads once and writes on demand, so a change on disk since that read rejects the write.
+function Markdown({ file, tab }) {
+  const [text, setText] = useState(null);
+  const [status, setStatus] = useState("");
+  useEffect(() => { file.readText().then(setText); }, [file]);
+  const save = (next) => {
+    tab.setModified(true);
+    file.writeText(next).then(
+      () => { tab.setModified(false); setText(next); },
+      (error) => setStatus(error instanceof PluginFileConflictError ? "Write rejected: changed on disk" : String(error)),
+    );
+  };
+  if (text === null) return <Loading />;
+  return <View>
+    <Text>Plugin Markdown: {text}</Text>
+    <Pressable accessibilityRole="button" onPress={() => save("# Saved by plugin\\n")}>
+      <Text>Edit Markdown through plugin</Text>
+    </Pressable>
+    <Text>{status}</Text>
+  </View>;
+}
+export default function contribute(client) {
+  client.addFilePanel({ id: "pdf", title: "PDF", icon: "FileText",
+    files: { extensions: ["pdf", "txt"] }, Component: Pdf });
+  client.addFilePanel({ id: "markdown", title: "Plugin Markdown", icon: "FileText",
+    files: { extensions: ["md"] }, Component: Markdown });
+  return () => {};
+}`;
+
+async function openWorkspaceFile(page: Page, name: string) {
+  await openFileFromExplorer(page, name);
+  await expectFileTabOpen(page, name);
+}
+async function associateMarkdownWithPlugin(page: Page) {
+  await page.evaluate(() => {
+    const key = "@paseo:app-settings";
+    const settings = JSON.parse(localStorage.getItem(key) ?? "{}");
+    settings.filePanelAssociations = { "ext:md": "plugin:file-panel-e2e/markdown" };
+    localStorage.setItem(key, JSON.stringify(settings));
+  });
+  await page.reload();
+}
+async function editMarkdownThroughPlugin(page: Page) {
+  await page.getByRole("button", { name: "Edit Markdown through plugin", exact: true }).click();
+}
+async function selectSource(page: Page) {
+  await page
+    .getByTestId("file-panel-switcher")
+    .filter({ visible: true })
+    .getByRole("button", { name: "Source", exact: true })
+    .click();
+}
+
+test("directory plugins render PDF bytes and write Markdown through the file handle", async ({
+  page,
+}, testInfo) => {
+  test.setTimeout(120_000);
+  const directory = await mkdtemp(path.join(tmpdir(), "paseo-file-panels-plugin-"));
+  const workspace = await seedWorkspace({
+    repoPrefix: "file-panels-",
+    repo: {
+      files: [
+        { path: "notes.md", content: "# Built-in Markdown\n" },
+        { path: "bytes.txt", content: "Bytes panel text document" },
+      ],
+    },
+  });
+  const client = await connectNewWorkspaceDaemonClient({ ownProjects: false });
+  const previousConfig = await client.getDaemonConfig();
+  await writeFile(path.join(workspace.repoPath, "report.pdf"), PDF);
+  await writeFile(
+    path.join(directory, "paseo-plugin.json"),
+    JSON.stringify({ id: PLUGIN_ID, requirements: pluginRequirements }),
+  );
+  await writeFile(path.join(directory, "index.client.tsx"), SOURCE);
+  try {
+    await client.patchDaemonConfig({ pluginsEnabled: true });
+    await client.installDirectoryPlugin(directory);
+    await page.setViewportSize({ width: 1280, height: 900 });
+    const gate = await installDaemonWebSocketGate(page);
+    await gotoWorkspace(page, workspace.workspaceId);
+    await openFileExplorer(page);
+    await openWorkspaceFile(page, "report.pdf");
+    await expect(page.getByText("PDF plugin: report.pdf", { exact: true })).toBeVisible();
+    await expect(
+      page.getByText(`Bytes ${PDF.length}; URL bytes ${PDF.length}`, { exact: true }),
+    ).toBeVisible();
+    await expect(
+      page.getByText(`Workspace ${workspace.workspaceId}`, { exact: true }),
+    ).toBeVisible();
+    await expect(page.getByTitle("Document preview", { exact: true })).toHaveAttribute(
+      "src",
+      /^blob:/,
+    );
+    await expect(
+      page.getByText(`Path ${path.join(workspace.repoPath, "report.pdf")}`, { exact: true }),
+    ).toBeVisible();
+    const pdfScreenshot = testInfo.outputPath("plugin-pdf-web.png");
+    await page.screenshot({ path: pdfScreenshot });
+    await testInfo.attach("plugin-pdf-web", { path: pdfScreenshot, contentType: "image/png" });
+
+    // A plugin panel claiming a text file competes with Source, so Paseo asks over the plugin.
+    await openWorkspaceFile(page, "bytes.txt");
+    await expect(page.getByText("Open .txt files with", { exact: true })).toBeVisible();
+    await page.keyboard.press("Escape");
+    await expect(page.getByText("Open .txt files with", { exact: true })).toBeHidden();
+    await expect(page.getByText("PDF plugin: bytes.txt", { exact: true })).toBeVisible();
+    await expect(page.getByTitle("Document preview", { exact: true })).toBeVisible();
+    await expect(page.getByTitle("Document preview", { exact: true })).toHaveAttribute(
+      "sandbox",
+      "",
+    );
+    await expect(
+      page
+        .frameLocator('[title="Document preview"]')
+        .getByText("Bytes panel text document", { exact: true }),
+    ).toBeVisible();
+
+    await openWorkspaceFile(page, "notes.md");
+    await expect(page.getByText("Open .md files with", { exact: true })).toBeVisible();
+    await page.keyboard.press("Escape");
+    await expect(page.getByText("Open .md files with", { exact: true })).toBeHidden();
+    await expect(
+      page.getByRole("heading", { name: "Built-in Markdown", exact: true }),
+    ).toBeVisible();
+    await expect(page.getByRole("button", { name: "Edit Markdown through plugin" })).toHaveCount(0);
+    await associateMarkdownWithPlugin(page);
+    await expect(
+      page.getByText("Plugin Markdown: # Built-in Markdown", { exact: true }),
+    ).toBeVisible();
+    gate.holdNextClientRequest("fs.file.write.request");
+    await editMarkdownThroughPlugin(page);
+    await gate.waitForHeldClientRequest();
+    await expect(page.getByTestId("workspace-tab-modified-file_notes.md")).toBeVisible();
+    gate.releaseHeldClientRequest();
+    await expect(
+      page.getByText("Plugin Markdown: # Saved by plugin", { exact: true }),
+    ).toBeVisible();
+    await expect
+      .poll(() => readFile(path.join(workspace.repoPath, "notes.md"), "utf8"))
+      .toBe("# Saved by plugin\n");
+    await expect(page.getByTestId("workspace-tab-modified-file_notes.md")).toBeHidden();
+
+    // The disk changed since the plugin's last read or write: the write is rejected, not applied.
+    await writeFile(path.join(workspace.repoPath, "notes.md"), "# Changed outside\n");
+    await editMarkdownThroughPlugin(page);
+    await expect(page.getByText("Write rejected: changed on disk", { exact: true })).toBeVisible();
+    expect(await readFile(path.join(workspace.repoPath, "notes.md"), "utf8")).toBe(
+      "# Changed outside\n",
+    );
+    await expect(page.getByTestId("workspace-tab-modified-file_notes.md")).toBeVisible();
+    let closePrompt = "";
+    page.once("dialog", async (dialog) => {
+      closePrompt = dialog.message();
+      await dialog.dismiss();
+    });
+    await page
+      .getByTestId("workspace-tab-file_notes.md")
+      .filter({ visible: true })
+      .first()
+      .click({ button: "right" });
+    await page.getByRole("menuitem", { name: "Close", exact: true }).click();
+    await expect.poll(() => closePrompt).toContain("discard");
+
+    await selectSource(page);
+    await expect(
+      page.getByTestId("file-source-editor").filter({ visible: true }).locator(".cm-content"),
+    ).toHaveText("# Changed outside");
+    const markdownScreenshot = testInfo.outputPath("plugin-markdown-source-web.png");
+    await page.screenshot({ path: markdownScreenshot });
+    await testInfo.attach("plugin-markdown-source-web", {
+      path: markdownScreenshot,
+      contentType: "image/png",
+    });
+  } finally {
+    await client.removePlugin(PLUGIN_ID);
+    await client.patchDaemonConfig({
+      pluginsEnabled: previousConfig.config.pluginsEnabled ?? false,
+    });
+    await client.close();
+    await workspace.cleanup();
+    await rm(directory, { recursive: true, force: true });
+  }
+});

packages/app/e2e/browser/plugin-host-ui.spec.ts

@@ -5,10 +5,6 @@ import path from "node:path";
 import { expect, test, type Page } from "../support/fixtures";
 import { gotoAppShell } from "../support/helpers/app";
 import { connectNewWorkspaceDaemonClient } from "../support/helpers/new-workspace";
-import {
-  expectMobileAgentSidebarVisible,
-  openMobileAgentSidebar,
-} from "../support/helpers/sidebar";
 
 const PLUGIN_ID = "plugin-host-ui-e2e";
 
@@ -91,12 +87,6 @@ async function useCompactLayout(page: Page): Promise<void> {
   await page.setViewportSize({ width: 390, height: 844 });
 }
 
-async function reopenHostUiPluginFromCompactSidebar(page: Page): Promise<void> {
-  await openMobileAgentSidebar(page);
-  await expectMobileAgentSidebarVisible(page);
-  await page.getByRole("button", { name: "Host UI", exact: true }).click();
-}
-
 async function openPluginModal(page: Page): Promise<void> {
   await page.getByRole("button", { name: "Open plugin modal", exact: true }).click();
 }
@@ -158,7 +148,6 @@ test("plugin modal adapts its presentation and preserves host contexts", async (
 
     await test.step("compact layouts preserve host contexts inside a sheet", async () => {
       await useCompactLayout(page);
-      await reopenHostUiPluginFromCompactSidebar(page);
       await openPluginModal(page);
       await expectCompactPluginSheet(page);
       await savePluginIssue(page);

packages/app/e2e/browser/plugin-modal-body.spec.ts

@@ -2,10 +2,6 @@ import { copyPluginExample } from "../support/helpers/plugin-fixture";
 import { expect, test as base, type Page } from "../support/fixtures";
 import { gotoAppShell } from "../support/helpers/app";
 import { connectNewWorkspaceDaemonClient } from "../support/helpers/new-workspace";
-import {
-  openMobileAgentSidebar,
-  expectMobileAgentSidebarVisible,
-} from "../support/helpers/sidebar";
 
 async function openExample(page: Page, example: string) {
   await page.getByRole("button", { name: `Open ${example}`, exact: true }).click();
@@ -122,9 +118,7 @@ async function openWideExamples(page: Page) {
 
 async function openCompactExamples(page: Page) {
   await page.setViewportSize({ width: 390, height: 844 });
-  await openMobileAgentSidebar(page);
-  await expectMobileAgentSidebarVisible(page);
-  await page.getByRole("button", { name: "Modal examples", exact: true }).click();
+  await expect(page.getByRole("button", { name: "Open Form", exact: true })).toBeVisible();
 }
 
 async function expectDeniedCopyFeedback(page: Page) {

packages/app/e2e/browser/sidebar-mobile-menu-sheets.spec.ts

@@ -15,6 +15,7 @@ async function closeMenuSheet(page: Page): Promise<void> {
 
 test("project and workspace kebabs open action sheets on compact layouts", async ({ page }) => {
   const seeded = await seedWorkspace({ repoPrefix: "sidebar-mobile-menu-sheet-" });
+  const secondProject = await seedWorkspace({ repoPrefix: "sidebar-mobile-menu-filter-" });
 
   try {
     await gotoAppShell(page);
@@ -26,6 +27,7 @@ test("project and workspace kebabs open action sheets on compact layouts", async
       /^Grouping/,
       /^Title/,
       "Show",
+      "Project",
       "Show background",
     ]);
     await closeMenuSheet(page);
@@ -53,6 +55,7 @@ test("project and workspace kebabs open action sheets on compact layouts", async
     });
     await expect(page.getByText("Workspace actions", { exact: true })).toBeVisible();
   } finally {
+    await secondProject.cleanup();
     await seeded.cleanup();
   }
 });

packages/app/e2e/browser/sidebar-workspace.spec.ts

@@ -624,7 +624,9 @@ test.describe("Half-screen desktop layout", () => {
     await expect(page.getByTestId("sidebar-settings")).not.toBeVisible();
   });
 
-  test("keeps app navigation beside the Explorer pane", async ({ page }) => {
+  test("yields app navigation to Explorer and restores it when Explorer closes", async ({
+    page,
+  }) => {
     const workspace = await seedWorkspace({ repoPrefix: "sidebar-half-screen-explorer-" });
 
     try {
@@ -636,7 +638,7 @@ test.describe("Half-screen desktop layout", () => {
       const explorerToggle = page.getByTestId("workspace-explorer-toggle").first();
       await expect(page.getByTestId("workspace-tab-files").filter({ visible: true })).toBeVisible();
       await expect(explorerToggle).toHaveAccessibleName("Close Explorer sidebar");
-      await expect(page.getByTestId("sidebar-global-new-workspace")).toBeVisible();
+      await expect(page.getByTestId("sidebar-global-new-workspace")).not.toBeVisible();
       await expect(page.getByTestId("workspace-explorer-sidebar")).toBeVisible();
       await expect(
         page

packages/app/e2e/browser/usage-modal.spec.ts

@@ -608,7 +608,10 @@ for (const compact of [false, true]) {
       if (compact) await openCompactSidebar(page);
       await openUsageFromIcon(page);
       await expectLoginErrors(page, ["Claude: Initial failure"]);
-      await expectLoginUsageFreshness(page, "No successful update", compact);
+      await test.step("developer errors do not interrupt freshness inspection", async () => {
+        await page.evaluate(() => console.error("E2E: developer toast while Usage is open"));
+        await expectLoginUsageFreshness(page, "No successful update", compact);
+      });
 
       await fixture.setReport({
         status: "available",

packages/app/e2e/mobile/agent-device/file-context-menu.ios.ad

@@ -4,8 +4,8 @@ env APP_ID=sh.paseo.debug
 open "${APP_ID}"
 wait "id=\"workspace-header-menu-trigger\"" 20000
 press "id=\"workspace-explorer-toggle\""
-wait "id=\"explorer-tab-files\"" 10000
-press "id=\"explorer-tab-files\""
+wait "id=\"workspace-tab-files\"" 10000
+press "id=\"workspace-tab-files\""
 wait "id=\"file-explorer-row-0\"" 10000
 longpress "id=\"file-explorer-row-0\"" 600
 wait "id=\"file-explorer-row-0-context-menu-content\"" 10000

packages/app/e2e/support/developer-ui.mjs

@@ -0,0 +1,15 @@
+const HIDE_DEVELOPER_TOASTS = "#error-toast { display: none !important; }";
+
+/** @param {import('@playwright/test').Page} page */
+export async function hideDeveloperToasts(page) {
+  // Developer chrome must not cover app actions or move the test's pointer/focus.
+  // Console errors remain in the runner's logs. Hiding the toast, instead of clicking it away,
+  // leaves no race with a toast that closes or is replaced between matching and clicking.
+  await page.addInitScript((css) => {
+    const style = document.createElement("style");
+    style.textContent = css;
+    document.addEventListener("DOMContentLoaded", () => document.head.append(style));
+  }, HIDE_DEVELOPER_TOASTS);
+  // A page attached after it loaded (Electron over CDP) runs no init script until it navigates.
+  await page.addStyleTag({ content: HIDE_DEVELOPER_TOASTS });
+}

packages/app/e2e/support/fixtures.ts

@@ -1,4 +1,5 @@
 import { test as base, expect, type Page } from "@playwright/test";
+import { hideDeveloperToasts } from "./developer-ui.mjs";
 import { startOutdatedDaemon, type OutdatedDaemon } from "./helpers/daemon-update";
 import { startE2EWorker } from "./helpers/e2e-worker";
 import { getE2EDaemonPort } from "./helpers/daemon-port";
@@ -130,6 +131,8 @@ const test = daemonTest.extend<{
         await ws.close({ code: 1008, reason: "Blocked connection to localhost:6767 during e2e." });
       });
 
+      await hideDeveloperToasts(page);
+
       const entries: string[] = [];
 
       page.on("console", (message) => {

packages/app/e2e/support/global-setup.ts

@@ -134,6 +134,8 @@ function startMetro(port: number, buffer: ReturnType<typeof createLineBuffer>):
     env: {
       ...process.env,
       BROWSER: "none",
+      // Automation never opens native DevTools or installs its desktop shell.
+      EXPO_UNSTABLE_HEADLESS: "1",
       ...(process.env.E2E_DESKTOP_RUNTIME === "1" ? { PASEO_WEB_PLATFORM: "electron" } : {}),
     },
     stdio: ["ignore", "pipe", "pipe"],

packages/app/e2e/support/helpers/composer.ts

@@ -363,10 +363,11 @@ export async function resizeComposerViewport(
   await page.setViewportSize(sizes[orientation]);
   // Before the app has loaded there is no layout to wait for.
   if (page.url() === "about:blank") return;
-  // Crossing the compact breakpoint remounts the shell and the editor. Anything that
-  // follows (a shortcut, a locator) belongs to the layout the new size implies, so
-  // wait for that layout before returning.
-  await expect(page.getByTestId("compact-shell")).toHaveCount(orientation === "landscape" ? 0 : 1);
+  // The shell and editor survive the breakpoint. Wait for the shell's layout
+  // marker to update before interacting with the resized composer.
+  await expect(
+    page.getByTestId(orientation === "landscape" ? "wide-shell" : "compact-shell"),
+  ).toBeVisible();
 }
 export async function selectComposerDraftRange(
   page: Page,

packages/app/e2e/support/helpers/context-window.ts

@@ -37,7 +37,7 @@ export async function hoverContextWindowMeter(page: Page, name = METER_NAME): Pr
   await page.getByRole("img", { name, exact: true }).hover({ timeout: 30_000 });
   const card = contextWindowDetails(page);
   await expect(card).toBeVisible();
-  await expect(card).toBeInViewport();
+  await expect(card).toBeInViewport({ ratio: 1 });
   return card;
 }
 

packages/app/e2e/support/helpers/markdown-file-panel-plugin.ts

@@ -0,0 +1,77 @@
+import { mkdtemp, rm, writeFile } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import path from "node:path";
+import { expect, type Page } from "@playwright/test";
+import { pluginRequirements } from "./plugin-fixture";
+import { connectNewWorkspaceDaemonClient } from "./new-workspace";
+import { expectFileTabOpen, openFileFromExplorer } from "./file-explorer";
+
+/** A directory plugin whose "Rich Markdown" file panel claims `.md`, next to the built-in. */
+export const MARKDOWN_PANEL_PLUGIN_ID = "file-panel-picker-e2e";
+export const MARKDOWN_PANEL_ID = `plugin:${MARKDOWN_PANEL_PLUGIN_ID}/rich-markdown`;
+export const BUILTIN_MARKDOWN_OPTION = "Markdown — Paseo";
+export const PLUGIN_MARKDOWN_OPTION = `Rich Markdown — ${MARKDOWN_PANEL_PLUGIN_ID}`;
+export const SOURCE_OPTION = "Source — Paseo";
+
+const SOURCE = `import React from "react";
+import { Text, View } from "react-native";
+function RichMarkdown({ file }) {
+  return <View><Text>Rich Markdown plugin: {file.name}</Text></View>;
+}
+export default function contribute(client) {
+  client.addFilePanel({ id: "rich-markdown", title: "Rich Markdown", icon: "FileType",
+    files: { extensions: ["md"] }, Component: RichMarkdown });
+  return () => {};
+}`;
+
+/** Enables plugins on the test daemon and installs the plugin; `uninstall` restores both. */
+export async function installMarkdownPanelPlugin(): Promise<{ uninstall(): Promise<void> }> {
+  const directory = await mkdtemp(path.join(tmpdir(), "paseo-markdown-file-panel-"));
+  const client = await connectNewWorkspaceDaemonClient({ ownProjects: false });
+  const previousConfig = await client.getDaemonConfig();
+  const uninstall = async () => {
+    await client.removePlugin(MARKDOWN_PANEL_PLUGIN_ID);
+    await client.patchDaemonConfig({
+      pluginsEnabled: previousConfig.config.pluginsEnabled ?? false,
+    });
+    await client.close();
+    await rm(directory, { recursive: true, force: true });
+  };
+  try {
+    await writeFile(
+      path.join(directory, "paseo-plugin.json"),
+      JSON.stringify({ id: MARKDOWN_PANEL_PLUGIN_ID, requirements: pluginRequirements }),
+    );
+    await writeFile(path.join(directory, "index.client.tsx"), SOURCE);
+    await client.patchDaemonConfig({ pluginsEnabled: true });
+    await client.installDirectoryPlugin(directory);
+  } catch (error) {
+    await uninstall();
+    throw error;
+  }
+  return { uninstall };
+}
+
+export function filePanelPicker(page: Page) {
+  return page.getByText("Open .md files with", { exact: true });
+}
+
+export async function openMarkdown(page: Page, name: string): Promise<void> {
+  await openFileFromExplorer(page, name);
+  await expectFileTabOpen(page, name);
+}
+
+export async function expectBuiltinMarkdown(page: Page, heading: string): Promise<void> {
+  await expect(page.getByRole("heading", { name: heading, exact: true })).toBeVisible();
+}
+
+export async function expectPluginMarkdown(page: Page, name: string): Promise<void> {
+  await expect(page.getByText(`Rich Markdown plugin: ${name}`, { exact: true })).toBeVisible();
+}
+
+export async function storedFilePanelAssociations(page: Page): Promise<unknown> {
+  return page.evaluate(() => {
+    const settings = JSON.parse(localStorage.getItem("@paseo:app-settings") ?? "{}");
+    return settings.filePanelAssociations ?? {};
+  });
+}

packages/app/e2e/support/helpers/settings.ts

@@ -24,6 +24,7 @@ const SECTION_LABELS = {
   appearance: "Appearance",
   sidebar: "Sidebar",
   editor: "Editor",
+  files: "Files",
   terminal: "Terminal",
   browser: "Browser",
   shortcuts: "Shortcuts",

packages/app/e2e/support/helpers/sidebar.ts

@@ -276,15 +276,22 @@ export async function swipeOpenMobileExplorer(page: Page): Promise<void> {
 }
 
 export async function closeMobileExplorer(page: Page): Promise<void> {
-  const closeButton = page.getByTestId("explorer-close");
+  const closeButton = page
+    .getByTestId("workspace-explorer-sidebar")
+    .getByRole("button", { name: "Close Explorer sidebar", exact: true });
   await expect(closeButton).toBeInViewport({ ratio: 1, timeout: 5_000 });
   await closeButton.click();
 }
 
 export async function expectMobileExplorerVisible(page: Page): Promise<void> {
-  await expect(page.getByTestId("explorer-header")).toBeInViewport({ ratio: 1, timeout: 5_000 });
+  await expect(page.getByTestId("workspace-explorer-sidebar")).toBeInViewport({
+    ratio: 1,
+    timeout: 5_000,
+  });
 }
 
 export async function expectMobileExplorerHidden(page: Page): Promise<void> {
-  await expect(page.getByTestId("explorer-header")).not.toBeInViewport({ timeout: 5_000 });
+  await expect(page.getByTestId("workspace-explorer-sidebar")).not.toBeInViewport({
+    timeout: 5_000,
+  });
 }

packages/app/package.json

@@ -58,11 +58,11 @@
     "@marijn/find-cluster-break": "^1.0.2",
     "@mattermost/react-native-paste-input": "2.0.1",
     "@react-native-async-storage/async-storage": "2.2.0",
-    "@react-native-masked-view/masked-view": "^0.3.2",
-    "@react-native/normalize-colors": "^0.81.5",
+    "@react-native-masked-view/masked-view": "0.3.2",
+    "@react-native/normalize-colors": "0.86.3",
     "@react-navigation/native": "^7.1.8",
     "@replit/codemirror-vim": "6.3.0",
-    "@shopify/react-native-skia": "2.2.12",
+    "@shopify/react-native-skia": "2.6.2",
     "@tanstack/react-query": "^5.90.11",
     "@tanstack/react-virtual": "^3.13.21",
     "@xterm/addon-clipboard": "^0.3.0-beta.213",
@@ -75,30 +75,30 @@
     "@xterm/addon-webgl": "^0.20.0-beta.212",
     "@xterm/xterm": "^6.1.0-beta.213",
     "buffer": "^6.0.3",
-    "expo": "^54.0.18",
-    "expo-asset": "~12.0.12",
-    "expo-audio": "~1.0.13",
-    "expo-build-properties": "^1.0.9",
-    "expo-camera": "~17.0.10",
-    "expo-clipboard": "~8.0.7",
-    "expo-constants": "~18.0.9",
-    "expo-crypto": "^15.0.8",
-    "expo-dev-client": "^6.0.15",
-    "expo-document-picker": "~14.0.8",
-    "expo-file-system": "~19.0.17",
-    "expo-haptics": "~15.0.7",
-    "expo-image": "~3.0.10",
-    "expo-image-manipulator": "~14.0.8",
-    "expo-image-picker": "^17.0.8",
-    "expo-keep-awake": "^15.0.7",
-    "expo-linking": "~8.0.8",
-    "expo-localization": "~17.0.9",
-    "expo-notifications": "^0.32.16",
-    "expo-router": "~6.0.13",
-    "expo-sharing": "^14.0.8",
-    "expo-splash-screen": "~31.0.10",
-    "expo-sqlite": "~16.0.10",
-    "expo-system-ui": "~6.0.7",
+    "expo": "~57.0.30",
+    "expo-asset": "~57.0.20",
+    "expo-audio": "~57.0.5",
+    "expo-build-properties": "~57.0.22",
+    "expo-camera": "~57.0.6",
+    "expo-clipboard": "~57.0.2",
+    "expo-constants": "~57.0.22",
+    "expo-crypto": "~57.0.4",
+    "expo-dev-client": "~57.0.20",
+    "expo-document-picker": "~57.0.3",
+    "expo-file-system": "~57.0.7",
+    "expo-haptics": "~57.0.3",
+    "expo-image": "~57.0.5",
+    "expo-image-manipulator": "~57.0.21",
+    "expo-image-picker": "~57.0.20",
+    "expo-keep-awake": "~57.0.2",
+    "expo-linking": "~57.0.13",
+    "expo-localization": "~57.0.2",
+    "expo-notifications": "~57.0.23",
+    "expo-router": "~57.0.28",
+    "expo-sharing": "~57.0.23",
+    "expo-splash-screen": "~57.0.10",
+    "expo-sqlite": "~57.0.4",
+    "expo-system-ui": "~57.0.4",
     "fast-deep-equal": "^3.1.3",
     "htmlparser2": "^12.0.0",
     "i18next": "^26.3.0",
@@ -111,25 +111,25 @@
     "micromark-util-decode-string": "2.0.1",
     "mnemonic-id": "^3.2.7",
     "qrcode": "^1.5.4",
-    "react": "19.1.0",
-    "react-dom": "19.1.0",
+    "react": "19.2.3",
+    "react-dom": "19.2.3",
     "react-freeze": "1.0.4",
     "react-i18next": "^17.0.8",
-    "react-native": "0.81.5",
+    "react-native": "0.86.3",
     "react-native-draggable-flatlist": "^4.0.3",
     "react-native-edge-to-edge": "^1.7.0",
     "react-native-enriched-markdown": "1.2.0-nightly-20261014-766fc0e67",
-    "react-native-gesture-handler": "~2.28.0",
+    "react-native-gesture-handler": "~2.32.0",
     "react-native-keyboard-controller": "1.21.12",
     "react-native-nitro-modules": "0.35.5",
-    "react-native-reanimated": "~4.3.1",
-    "react-native-safe-area-context": "~5.6.0",
-    "react-native-screens": "~4.16.0",
-    "react-native-svg": "^15.14.0",
+    "react-native-reanimated": "4.5.1",
+    "react-native-safe-area-context": "~5.7.0",
+    "react-native-screens": "~4.26.0",
+    "react-native-svg": "15.15.4",
     "react-native-unistyles": "^3.2.4",
     "react-native-web": "~0.21.0",
-    "react-native-webview": "^13.16.0",
-    "react-native-worklets": "~0.8.3",
+    "react-native-webview": "13.16.1",
+    "react-native-worklets": "0.10.1",
     "tiny-invariant": "^1.3.3",
     "turndown": "^7.2.4",
     "turndown-plugin-gfm": "^1.0.2",
@@ -151,11 +151,12 @@
     "@vitest/browser": "^4.1.7",
     "@vitest/browser-playwright": "^4.1.7",
     "@xterm/headless": "^6.1.0-beta.213",
+    "babel-preset-expo": "~57.0.16",
     "dotenv": "^17.2.3",
     "eas-cli": "^16.24.1",
     "esbuild": "0.28.1",
     "eslint": "^9.25.0",
-    "eslint-config-expo": "~10.0.0",
+    "eslint-config-expo": "~57.0.2",
     "expo-gradle-jvmargs": "^1.1.2",
     "fake-indexeddb": "^6.2.5",
     "jsdom": "^20.0.3",

packages/app/plugins/with-paste-input.js

@@ -4,26 +4,33 @@ const {
   IOSConfig,
   withAppDelegate,
   withDangerousMod,
+  withInfoPlist,
   withPodfile,
 } = require("expo/config-plugins");
 
-const MODULE_SETUP = "    PasteInputModule.setup(factory.rootViewFactory)";
-const REACT_NATIVE_START_END = "      launchOptions: launchOptions)\n#endif";
 const BRIDGING_HEADER_IMPORT = "#import <react-native-paste-input/PasteInputModule.h>";
-const PODFILE_NEW_ARCH_DISABLED =
-  "ENV['RCT_NEW_ARCH_ENABLED'] ||= '0' if podfile_properties['newArchEnabled'] == 'false'";
-const PODFILE_NEW_ARCH_ENABLED =
-  "ENV['RCT_NEW_ARCH_ENABLED'] ||= '1' if podfile_properties['newArchEnabled'] == 'true'";
+const SCENE_DELEGATE = `
+@objc(PaseoSceneDelegate)
+class PaseoSceneDelegate: ExpoAppSceneDelegate {
+  override func scene(
+    _ scene: UIScene,
+    willConnectTo session: UISceneSession,
+    options connectionOptions: UIScene.ConnectionOptions
+  ) {
+    super.scene(scene, willConnectTo: session, options: connectionOptions)
+    guard let provider = UIApplication.shared.delegate as? ExpoReactNativeFactoryProvider,
+      let factory = provider.reactNativeFactory else { return }
+    PasteInputModule.setup(factory.rootViewFactory)
+  }
+}
+`;
 
 function configurePasteInputAppDelegate(contents) {
-  const configured = contents.replace(`\n${MODULE_SETUP}`, "");
-  if (!configured.includes(REACT_NATIVE_START_END)) {
-    throw new Error("Could not register paste input after React Native starts");
+  if (contents.includes("class PaseoSceneDelegate:")) return contents;
+  if (!contents.includes("ExpoReactNativeFactoryProvider")) {
+    throw new Error("Paste input requires Expo scene support");
   }
-  return configured.replace(
-    REACT_NATIVE_START_END,
-    `      launchOptions: launchOptions)\n${MODULE_SETUP}\n#endif`,
-  );
+  return `${contents.trimEnd()}\n${SCENE_DELEGATE}`;
 }
 
 function configurePasteInputBridgingHeader(contents) {
@@ -33,19 +40,6 @@ function configurePasteInputBridgingHeader(contents) {
   return `${contents.trimEnd()}\n${BRIDGING_HEADER_IMPORT}\n`;
 }
 
-function configurePasteInputPodfile(contents) {
-  if (contents.includes(PODFILE_NEW_ARCH_ENABLED)) {
-    return contents;
-  }
-  if (!contents.includes(PODFILE_NEW_ARCH_DISABLED)) {
-    throw new Error("Could not configure the new architecture for paste input");
-  }
-  return contents.replace(
-    PODFILE_NEW_ARCH_DISABLED,
-    `${PODFILE_NEW_ARCH_DISABLED}\n${PODFILE_NEW_ARCH_ENABLED}`,
-  );
-}
-
 function withPasteInput(config) {
   const withDelegate = withAppDelegate(config, (modConfig) => {
     if (modConfig.modResults.language !== "swift") {
@@ -54,7 +48,18 @@ function withPasteInput(config) {
     modConfig.modResults.contents = configurePasteInputAppDelegate(modConfig.modResults.contents);
     return modConfig;
   });
-  const withPods = withPodfile(withDelegate, (modConfig) => {
+  const withScene = withInfoPlist(withDelegate, (modConfig) => {
+    const scenes =
+      modConfig.modResults.UIApplicationSceneManifest?.UISceneConfigurations
+        ?.UIWindowSceneSessionRoleApplication;
+    if (!scenes || scenes.length !== 1) {
+      throw new Error("Paste input requires Expo's single scene configuration");
+    }
+    scenes[0].UISceneDelegateClassName = "PaseoSceneDelegate";
+    return modConfig;
+  });
+  const withPods = withPodfile(withScene, (modConfig) => {
+    // Paste input checks this legacy flag even though RN 0.86 only supports Fabric.
     modConfig.modResults.contents = configurePasteInputPodfile(modConfig.modResults.contents);
     return modConfig;
   });
@@ -79,4 +84,9 @@ function withPasteInputBridgingHeader(config) {
 module.exports = withPasteInput;
 module.exports.configurePasteInputAppDelegate = configurePasteInputAppDelegate;
 module.exports.configurePasteInputBridgingHeader = configurePasteInputBridgingHeader;
+
+function configurePasteInputPodfile(contents) {
+  const flag = "ENV['RCT_NEW_ARCH_ENABLED'] = '1'";
+  return contents.includes(flag) ? contents : `${flag}\n${contents}`;
+}
 module.exports.configurePasteInputPodfile = configurePasteInputPodfile;

packages/app/plugins/with-paste-input.test.ts

@@ -7,22 +7,14 @@ const {
 } = require("./with-paste-input");
 
 describe("withPasteInput", () => {
-  it("registers the module after React Native starts", () => {
-    const source = [
-      "import ReactAppDependencyProvider",
-      "",
-      "    bindReactNativeFactory(factory)",
-      "    factory.startReactNative(",
-      '      withModuleName: "main",',
-      "      in: window,",
-      "      launchOptions: launchOptions)",
-      "#endif",
-    ].join("\n");
+  it("registers paste input after Expo connects the React Native scene", () => {
+    const source = "class AppDelegate: ExpoAppDelegate, ExpoReactNativeFactoryProvider {}";
     const configured = configurePasteInputAppDelegate(source);
-
-    expect(configured).toContain(
-      "      launchOptions: launchOptions)\n    PasteInputModule.setup(factory.rootViewFactory)\n#endif",
+    expect(configured).toContain("class PaseoSceneDelegate: ExpoAppSceneDelegate");
+    expect(configured.indexOf("super.scene(")).toBeLessThan(
+      configured.indexOf("PasteInputModule.setup("),
     );
+    expect(configured).toContain("provider.reactNativeFactory");
     expect(configurePasteInputAppDelegate(configured)).toBe(configured);
   });
 
@@ -33,15 +25,11 @@ describe("withPasteInput", () => {
     expect(configured).toContain("#import <react-native-paste-input/PasteInputModule.h>");
     expect(configurePasteInputBridgingHeader(configured)).toBe(configured);
   });
-
-  it("sets the new architecture environment before CocoaPods evaluates dependencies", () => {
+  it("enables the legacy new-architecture flag required by the paste input podspec", () => {
     const source =
-      "ENV['RCT_NEW_ARCH_ENABLED'] ||= '0' if podfile_properties['newArchEnabled'] == 'false'";
+      "require File.join(File.dirname(`node --print \"require.resolve('expo/package.json')\"`), 'scripts/autolinking')";
     const configured = configurePasteInputPodfile(source);
-
-    expect(configured).toContain(
-      "ENV['RCT_NEW_ARCH_ENABLED'] ||= '1' if podfile_properties['newArchEnabled'] == 'true'",
-    );
+    expect(configured).toBe("ENV['RCT_NEW_ARCH_ENABLED'] = '1'\n" + source);
     expect(configurePasteInputPodfile(configured)).toBe(configured);
   });
 });

packages/app/src/agent-skills/index.tsx

@@ -1,7 +1,7 @@
 import { useCallback, useMemo, useState } from "react";
 import { useTranslation } from "react-i18next";
 import { Text, View } from "react-native";
-import { useFocusEffect } from "@react-navigation/native";
+import { useFocusEffect } from "expo-router/react-navigation";
 import { StyleSheet, withUnistyles } from "react-native-unistyles";
 import { ArrowUpRight, Blocks, Check, Settings2 } from "lucide-react-native";
 import type { AgentSkillOperation, AgentSkillsStatus } from "@getpaseo/protocol/messages";

packages/app/src/agent-stream/view.tsx

@@ -445,11 +445,6 @@ const AgentStreamViewComponent = forwardRef<AgentStreamViewHandle, AgentStreamVi
           serverId: resolvedServerId,
           workspaceId: context.workspaceId ?? "",
         }),
-        checkout: {
-          serverId: resolvedServerId,
-          cwd: context.cwd,
-          isGit: context.projectPlacement?.checkout?.isGit ?? true,
-        },
         view: "files",
       });
     });

packages/app/src/app/_layout.tsx

@@ -1,3 +1,6 @@
+import { useSafeAreaInsets } from "react-native-safe-area-context";
+import { useActiveWorkspaceSelection } from "@/stores/navigation-active-workspace-store";
+import { useIsExplorerSidebarOpen } from "@/workspace-tabs/explorer-sidebar";
 import { ComposerEditingSessionsProvider } from "@/composer/editing-session";
 import "@/styles/unistyles";
 import { BottomSheetModalProvider } from "@gorhom/bottom-sheet";
@@ -41,7 +44,7 @@ import { DesktopWindowControls } from "@/components/desktop/window-controls";
 import { SidebarModelProvider } from "@/components/sidebar/sidebar-model";
 import { WorkspacePinShortcutHandler } from "@/components/workspace-pin-shortcut-handler";
 import { WorkspaceRenameHost } from "@/components/workspace-rename-host";
-import { CompactExplorerSidebarHost } from "@/components/compact-explorer-sidebar-host";
+import { WorkspaceExplorerOpenGesture } from "@/mobile-panels/explorer-open-gesture";
 import { ProviderSettingsHost } from "@/components/provider-settings-host";
 import { WorkspaceSetupDialog } from "@/components/workspace-setup-dialog";
 import { WorkspaceShortcutTargetsSubscriber } from "@/components/workspace-shortcut-targets-subscriber";
@@ -90,7 +93,6 @@ import { useGlobalNewWorkspaceAction } from "@/hooks/use-global-new-workspace-ac
 import { useLatchedBoolean } from "@/hooks/use-latched-boolean";
 import { useFaviconStatus } from "@/hooks/use-favicon-status";
 import { useKeyboardShortcuts } from "@/hooks/use-keyboard-shortcuts";
-import { resolveExplorerSidebarPresentation } from "@/workspace-tabs/explorer-sidebar";
 import { KeyboardShiftProvider } from "@/keyboard/shift";
 import { useCompactWebViewportZoomLock } from "@/hooks/use-compact-web-viewport-zoom-lock";
 import { useOpenProject } from "@/hooks/use-open-project";
@@ -468,17 +470,15 @@ function AppContainer({ children, chromeEnabled: chromeEnabledOverride }: AppCon
   const isFocusModeEnabled = usePanelStore((state) => state.desktop.focusModeEnabled);
   const isDesktopAgentListOpen = usePanelStore((state) => state.desktop.agentListOpen);
   const sidebarWidth = usePanelStore((state) => state.sidebarWidth);
-  const { width: viewportWidth } = useWindowDimensions();
+  const { width: windowWidth } = useWindowDimensions();
+  const insets = useSafeAreaInsets();
+  const viewportWidth = windowWidth - insets.left - insets.right;
 
   const cycleTheme = useCallback(() => {
     void updateSettings({ theme: getNextThemePreference(settings.theme) });
   }, [settings.theme, updateSettings]);
 
   const isCompactLayout = useIsCompactFormFactor();
-  const explorerSidebarPresentation = resolveExplorerSidebarPresentation({
-    isCompact: isCompactLayout,
-  });
-  const usesCompactExplorerHost = explorerSidebarPresentation !== "pane";
   useCompactWebViewportZoomLock(isCompactLayout);
   const pathname = usePathname();
   const isWorkspaceRoute = parseHostWorkspaceRouteFromPathname(pathname) !== null;
@@ -516,7 +516,15 @@ function AppContainer({ children, chromeEnabled: chromeEnabledOverride }: AppCon
   useActiveWorktreeNewAction();
   useGlobalNewWorkspaceAction();
 
+  const activeWorkspace = useActiveWorkspaceSelection();
+  const explorerVisible = useIsExplorerSidebarOpen({
+    isCompact: isCompactLayout,
+    workspaceKey: activeWorkspace
+      ? `${activeWorkspace.serverId}:${activeWorkspace.workspaceId}`
+      : null,
+  });
   const appContentMinimumWidth = resolveDesktopAppContentMinimum({
+    explorerVisible: isWorkspaceRoute && explorerVisible,
     isSettingsRoute: pathname.includes("/settings"),
   });
   const desktopSidebarMounted = hasMountedDesktopSidebar && !isWorkspaceFocusModeEnabled;
@@ -548,28 +556,25 @@ function AppContainer({ children, chromeEnabled: chromeEnabledOverride }: AppCon
   if (isWeb) {
     themedSidebarChrome = <AppearanceStyleBoundary>{sidebarChrome}</AppearanceStyleBoundary>;
   }
+  const workspaceChromeStyle = useMemo(
+    () => [rowStyle, !isCompactLayout && { paddingLeft: insets.left, paddingRight: insets.right }],
+    [insets.left, insets.right, isCompactLayout],
+  );
   const workspaceChrome = (
-    <View style={rowStyle}>
+    <View style={workspaceChromeStyle}>
       <WorkspaceLayoutModePublisher />
       {!isCompactLayout ? (
         <WindowChromeRegion corners={appChromeLayout.sidebarCorners}>
           {themedSidebarChrome}
         </WindowChromeRegion>
       ) : null}
-      {usesCompactExplorerHost ? (
-        <CompactExplorerSidebarHost
-          enabled={chromeEnabled}
-          presentation={explorerSidebarPresentation === "dock" ? "dock" : "overlay"}
+      <WorkspaceExplorerOpenGesture enabled={chromeEnabled && isCompactLayout}>
+        <WindowChromeRegion
+          corners={isCompactLayout && chromeEnabled ? "both" : appChromeLayout.contentCorners}
         >
-          <WindowChromeRegion corners={chromeEnabled ? "both" : appChromeLayout.contentCorners}>
-            <View style={flexStyle}>{children}</View>
-          </WindowChromeRegion>
-        </CompactExplorerSidebarHost>
-      ) : (
-        <WindowChromeRegion corners={appChromeLayout.contentCorners}>
           <View style={flexStyle}>{children}</View>
         </WindowChromeRegion>
-      )}
+      </WorkspaceExplorerOpenGesture>
     </View>
   );
 
@@ -620,15 +625,27 @@ function AppContainer({ children, chromeEnabled: chromeEnabledOverride }: AppCon
     </View>
   );
 
-  const content = isCompactLayout ? (
-    <MobileGestureWrapper chromeEnabled={chromeEnabled}>{surface}</MobileGestureWrapper>
-  ) : (
-    surface
+  return (
+    <AppContainerLifetime compactGesturesEnabled={chromeEnabled && isCompactLayout}>
+      {surface}
+    </AppContainerLifetime>
   );
+}
 
+function AppContainerLifetime({
+  children,
+  compactGesturesEnabled,
+}: {
+  children: ReactNode;
+  compactGesturesEnabled: boolean;
+}) {
   return (
     <ComposerEditingSessionsProvider>
-      <CommandCenterProvider>{content}</CommandCenterProvider>
+      <CommandCenterProvider>
+        <MobileGestureWrapper chromeEnabled={compactGesturesEnabled}>
+          {children}
+        </MobileGestureWrapper>
+      </CommandCenterProvider>
     </ComposerEditingSessionsProvider>
   );
 }
@@ -662,10 +679,15 @@ function MobileGestureWrapper({
   chromeEnabled: boolean;
 }) {
   const openGesture = useOpenAgentListGesture(chromeEnabled);
+  const isCompactLayout = useIsCompactFormFactor();
 
   return (
     <GestureDetector gesture={openGesture} touchAction={MOBILE_WEB_GESTURE_TOUCH_ACTION}>
-      <View collapsable={false} style={layoutStyles.surfaceFill} testID="compact-shell">
+      <View
+        collapsable={false}
+        style={layoutStyles.surfaceFill}
+        testID={isCompactLayout ? "compact-shell" : "wide-shell"}
+      >
         {children}
       </View>
     </GestureDetector>

packages/app/src/app/h/[serverId]/_layout.tsx

@@ -10,6 +10,8 @@ const HOST_STACK_SCREEN_OPTIONS = {
   animation: "none" as const,
 };
 
+const SCREEN_OWNED_APPEARANCE = ["workspace/[workspaceId]/index"] as const;
+
 const AGENT_SCREEN_OPTIONS = { gestureEnabled: false };
 
 export default function HostRouteLayout() {
@@ -34,7 +36,10 @@ function KnownHostRoute() {
   }
 
   const stack = (
-    <ThemedStack screenOptions={HOST_STACK_SCREEN_OPTIONS}>
+    <ThemedStack
+      screenOptions={HOST_STACK_SCREEN_OPTIONS}
+      screenOwnedAppearance={SCREEN_OWNED_APPEARANCE}
+    >
       <Stack.Screen name="index" />
       <Stack.Screen name="workspace/[workspaceId]/index" />
       <Stack.Screen name="agent/[agentId]" options={AGENT_SCREEN_OPTIONS} />

packages/app/src/app/h/[serverId]/workspace/[workspaceId]/index.tsx

@@ -1,5 +1,5 @@
 import { useCallback, useEffect, useLayoutEffect, useMemo, useRef, useState } from "react";
-import { useNavigation } from "@react-navigation/native";
+import { useNavigation } from "expo-router/react-navigation";
 import { StyleSheet, View } from "react-native";
 import { useGlobalSearchParams, useLocalSearchParams, useRootNavigationState } from "expo-router";
 import { HostRouteBootstrapBoundary } from "@/components/host-route-bootstrap-boundary";

packages/app/src/app/pair-scan.tsx

@@ -33,7 +33,7 @@ const styles = StyleSheet.create((theme) => ({
     flex: 1,
   },
   overlay: {
-    ...StyleSheet.absoluteFillObject,
+    ...StyleSheet.absoluteFill,
     justifyContent: "center",
     alignItems: "center",
   },

packages/app/src/command-center/command-center.tsx

@@ -943,7 +943,7 @@ const styles = StyleSheet.create((theme) => ({
     alignItems: "center",
     paddingTop: theme.spacing[12],
   },
-  backdrop: { ...StyleSheet.absoluteFillObject, backgroundColor: "rgba(0, 0, 0, 0.5)" },
+  backdrop: { ...StyleSheet.absoluteFill, backgroundColor: "rgba(0, 0, 0, 0.5)" },
   panel: {
     width: 640,
     height: 560,

packages/app/src/components/adaptive-modal-sheet.tsx

@@ -66,7 +66,7 @@ export interface SheetHeader {
 }
 
 const SCROLL_CONTENT_GROW = { flexGrow: 1 };
-const ABSOLUTE_FILL_STYLE = { ...StyleSheet.absoluteFillObject };
+const ABSOLUTE_FILL_STYLE = { ...StyleSheet.absoluteFill };
 const NATIVE_DIALOG_SNAP_POINTS = ["100%"];
 
 const styles = StyleSheet.create((theme) => ({
@@ -77,7 +77,7 @@ const styles = StyleSheet.create((theme) => ({
     backgroundColor: "transparent",
   },
   desktopOverlay: {
-    ...StyleSheet.absoluteFillObject,
+    ...StyleSheet.absoluteFill,
     backgroundColor: "rgba(0,0,0,0.55)",
     justifyContent: "center",
     alignItems: "center",

packages/app/src/components/add-project-flow.tsx

@@ -1007,7 +1007,7 @@ const styles = StyleSheet.create((theme) => ({
     paddingTop: theme.spacing[12],
   },
   backdrop: {
-    ...StyleSheet.absoluteFillObject,
+    ...StyleSheet.absoluteFill,
     backgroundColor: "rgba(0, 0, 0, 0.5)",
   },
   panel: {

packages/app/src/components/appearance-style-boundary.test.ts

@@ -20,54 +20,53 @@ describe("appearanceStyleBoundaryKey", () => {
 // This is a placement contract against the production JSX, not a simulated native mount.
 // Native Gesture Handler/Fabric lifetime behavior is verified on the release app.
 describe("retained native gesture host appearance placement", () => {
-  it.each([
-    ["../app/_layout.tsx", ["sidebarChrome", "themedSidebarChrome"]],
-    [
-      "./compact-explorer-sidebar-host.tsx",
-      ["explorer", "themedExplorer", "CompactExplorerSidebar", "NativeExplorerSidebarDock"],
-    ],
-  ] as const)("keeps native hosts outside appearance keys in %s", (path, hosts) => {
-    const source = ts.createSourceFile(
-      path,
-      readFileSync(new URL(path, import.meta.url), "utf8"),
-      ts.ScriptTarget.Latest,
-      true,
-      ts.ScriptKind.TSX,
-    );
-    let hostsFound = 0;
-    let webKeysFound = 0;
-    function visit(node: ts.Node) {
-      let name: string | undefined;
-      if (ts.isIdentifier(node)) name = node.text;
-      if (ts.isJsxSelfClosingElement(node)) name = node.tagName.getText(source);
-      if (name && hosts.some((host) => host === name)) {
-        hostsFound++;
-        let webOnly = false;
-        let keyed = false;
-        for (
-          let child = node, parent = node.parent;
-          parent;
-          child = parent, parent = parent.parent
-        ) {
-          if (
-            ts.isIfStatement(parent) &&
-            parent.expression.getText(source) === "isWeb" &&
-            parent.thenStatement === child
-          )
-            webOnly = true;
-          if (
-            ts.isJsxElement(parent) &&
-            parent.openingElement.tagName.getText(source) === "AppearanceStyleBoundary"
-          )
-            keyed = true;
+  it.each([["../app/_layout.tsx", ["sidebarChrome", "themedSidebarChrome"], true]] as const)(
+    "keeps native hosts outside appearance keys in %s",
+    (path, hosts, hasWebKeys) => {
+      const source = ts.createSourceFile(
+        path,
+        readFileSync(new URL(path, import.meta.url), "utf8"),
+        ts.ScriptTarget.Latest,
+        true,
+        ts.ScriptKind.TSX,
+      );
+      let hostsFound = 0;
+      let webKeysFound = 0;
+      function visit(node: ts.Node) {
+        let name: string | undefined;
+        if (ts.isIdentifier(node)) name = node.text;
+        if (ts.isJsxSelfClosingElement(node)) name = node.tagName.getText(source);
+        if (name && hosts.some((host) => host === name)) {
+          hostsFound++;
+          let webOnly = false;
+          let keyed = false;
+          for (
+            let child = node, parent = node.parent;
+            parent;
+            child = parent, parent = parent.parent
+          ) {
+            if (
+              ts.isIfStatement(parent) &&
+              parent.expression.getText(source) === "isWeb" &&
+              parent.thenStatement === child
+            )
+              webOnly = true;
+            if (
+              ts.isJsxElement(parent) &&
+              parent.openingElement.tagName.getText(source) === "AppearanceStyleBoundary"
+            )
+              keyed = true;
+          }
+          if (keyed && webOnly) webKeysFound++;
+          expect(keyed && !webOnly, `${name} is remounted on native appearance changes`).toBe(
+            false,
+          );
         }
-        if (keyed && webOnly) webKeysFound++;
-        expect(keyed && !webOnly, `${name} is remounted on native appearance changes`).toBe(false);
+        ts.forEachChild(node, visit);
       }
-      ts.forEachChild(node, visit);
-    }
-    visit(source);
-    expect(hostsFound).toBeGreaterThan(0);
-    expect(webKeysFound).toBeGreaterThan(0);
-  });
+      visit(source);
+      expect(hostsFound).toBeGreaterThan(0);
+      if (hasWebKeys) expect(webKeysFound).toBeGreaterThan(0);
+    },
+  );
 });

packages/app/src/components/compact-explorer-sidebar-host-state.test.ts

@@ -1,106 +0,0 @@
-import { describe, expect, it } from "vitest";
-import {
-  resolveCompactExplorerSidebarHostModel,
-  type CompactExplorerSidebarHostModel,
-} from "@/components/compact-explorer-sidebar-host-state";
-import type { WorkspaceDescriptor } from "@/stores/session-store";
-
-function createWorkspace(
-  input: Partial<WorkspaceDescriptor> & Pick<WorkspaceDescriptor, "id">,
-): WorkspaceDescriptor {
-  return {
-    id: input.id,
-    projectId: input.projectId ?? "project-1",
-    projectDisplayName: input.projectDisplayName ?? "Project 1",
-    projectRootPath: input.projectRootPath ?? "/repo",
-    workspaceDirectory: input.workspaceDirectory ?? "/repo",
-    projectKind: input.projectKind ?? "git",
-    workspaceKind: input.workspaceKind ?? "local_checkout",
-    name: input.name ?? "main",
-    status: input.status ?? "done",
-    archivingAt: input.archivingAt ?? null,
-    statusEnteredAt: null,
-    diffStat: input.diffStat ?? null,
-    scripts: input.scripts ?? [],
-  };
-}
-
-function createModel(
-  overrides: Partial<CompactExplorerSidebarHostModel> = {},
-): CompactExplorerSidebarHostModel {
-  return {
-    serverId: overrides.serverId ?? "server-1",
-    workspaceId: overrides.workspaceId ?? "workspace-a",
-    persistenceKey: overrides.persistenceKey ?? "server-1:workspace-a",
-    workspaceRoot: overrides.workspaceRoot ?? "/repo/a",
-    isGit: overrides.isGit ?? true,
-  };
-}
-
-describe("resolveCompactExplorerSidebarHostModel", () => {
-  it("retains the last workspace root for the same active selection while the workspace reloads", () => {
-    const previous = createModel();
-
-    const result = resolveCompactExplorerSidebarHostModel({
-      previous,
-      selection: { serverId: "server-1", workspaceId: "workspace-a" },
-      workspace: null,
-      isGit: false,
-    });
-
-    expect(result).toEqual({
-      serverId: "server-1",
-      workspaceId: "workspace-a",
-      persistenceKey: "server-1:workspace-a",
-      workspaceRoot: "/repo/a",
-      isGit: true,
-    });
-  });
-
-  it("switches ownership to the active workspace instead of leaking the previous one", () => {
-    const previous = createModel();
-
-    const result = resolveCompactExplorerSidebarHostModel({
-      previous,
-      selection: { serverId: "server-1", workspaceId: "workspace-b" },
-      workspace: null,
-      isGit: false,
-    });
-
-    expect(result).toEqual({
-      serverId: "server-1",
-      workspaceId: "workspace-b",
-      persistenceKey: "server-1:workspace-b",
-      workspaceRoot: "",
-      isGit: false,
-    });
-  });
-
-  it("does not retain a previous owner when there is no active workspace selection", () => {
-    const result = resolveCompactExplorerSidebarHostModel({
-      previous: createModel(),
-      selection: null,
-      workspace: null,
-      isGit: false,
-    });
-
-    expect(result).toBeNull();
-  });
-
-  it("uses the current workspace directory when it is available", () => {
-    const result = resolveCompactExplorerSidebarHostModel({
-      previous: null,
-      selection: { serverId: "server-1", workspaceId: "workspace-a" },
-      workspace: createWorkspace({ id: "workspace-a", workspaceDirectory: "/repo/current" }),
-      isGit: true,
-    });
-
-    expect(result).toEqual({
-      serverId: "server-1",
-      workspaceId: "workspace-a",
-      persistenceKey: "server-1:workspace-a",
-      workspaceRoot: "/repo/current",
-      isGit: true,
-    });
-  });
-});

packages/app/src/components/compact-explorer-sidebar-host-state.ts

@@ -1,59 +0,0 @@
-import { buildWorkspaceTabPersistenceKey } from "@/workspace-tabs/model";
-import type { ActiveWorkspaceSelection } from "@/stores/navigation-active-workspace-store";
-import type { WorkspaceDescriptor } from "@/stores/session-store";
-
-export interface CompactExplorerSidebarHostModel {
-  serverId: string;
-  workspaceId: string;
-  persistenceKey: string;
-  workspaceRoot: string;
-  isGit: boolean;
-}
-
-interface ResolveCompactExplorerSidebarHostModelInput {
-  previous: CompactExplorerSidebarHostModel | null;
-  selection: ActiveWorkspaceSelection | null;
-  workspace: WorkspaceDescriptor | null;
-  isGit: boolean;
-}
-
-function trimNonEmpty(value: string | null | undefined): string | null {
-  if (typeof value !== "string") {
-    return null;
-  }
-  const trimmed = value.trim();
-  return trimmed.length > 0 ? trimmed : null;
-}
-
-export function resolveCompactExplorerSidebarHostModel(
-  input: ResolveCompactExplorerSidebarHostModelInput,
-): CompactExplorerSidebarHostModel | null {
-  const serverId = trimNonEmpty(input.selection?.serverId);
-  const workspaceId = trimNonEmpty(input.selection?.workspaceId);
-  if (!serverId || !workspaceId) {
-    return null;
-  }
-
-  const persistenceKey = buildWorkspaceTabPersistenceKey({ serverId, workspaceId });
-  if (!persistenceKey) {
-    return null;
-  }
-
-  const previousForSelection =
-    input.previous &&
-    input.previous.serverId === serverId &&
-    input.previous.workspaceId === workspaceId
-      ? input.previous
-      : null;
-
-  return {
-    serverId,
-    workspaceId,
-    persistenceKey,
-    workspaceRoot:
-      trimNonEmpty(input.workspace?.workspaceDirectory) ??
-      previousForSelection?.workspaceRoot ??
-      "",
-    isGit: input.workspace ? input.isGit : (previousForSelection?.isGit ?? input.isGit),
-  };
-}

packages/app/src/components/compact-explorer-sidebar-host.tsx

@@ -1,216 +0,0 @@
-import { type ReactNode, useCallback, useEffect, useMemo, useRef, useState } from "react";
-import { View, type LayoutChangeEvent } from "react-native";
-import { GestureDetector } from "react-native-gesture-handler";
-import { useActiveWorkspaceSelection } from "@/stores/navigation-active-workspace-store";
-import { useWorkspace } from "@/stores/session-store-hooks";
-import {
-  CompactExplorerSidebar,
-  NativeExplorerSidebarDock,
-} from "@/components/compact-explorer-sidebar";
-import { useOpenFileExplorerGesture } from "@/mobile-panels/gestures";
-import { useIsMobilePanelActive } from "@/mobile-panels/provider";
-import { useHostRuntimeClient, useHostRuntimeIsConnected } from "@/runtime/host-runtime";
-import { usePanelStore } from "@/stores/panel-store";
-import { useWorkspaceLayoutStore } from "@/stores/workspace-layout-store";
-import type { WorkspaceTabTarget } from "@/workspace-tabs/model";
-import { useWorkspaceCheckoutStatus } from "@/screens/workspace/use-workspace-checkout-status";
-import { openWorkspaceFileFromExplorer } from "@/screens/workspace/workspace-file-open-command";
-import { isWeb } from "@/constants/platform";
-import { DiffDocumentWorkspaceCacheProvider } from "@/git/diff-document/workspace-cache";
-import {
-  resolveCompactExplorerSidebarHostModel,
-  type CompactExplorerSidebarHostModel,
-} from "@/components/compact-explorer-sidebar-host-state";
-import { AppearanceStyleBoundary } from "@/components/appearance-style-boundary";
-
-interface CompactExplorerOpenGestureSurfaceProps {
-  children: ReactNode;
-  enabled: boolean;
-  onOpenExplorer: () => void;
-}
-
-const COMPACT_WEB_GESTURE_TOUCH_ACTION = isWeb ? "auto" : "pan-y";
-
-function CompactExplorerOpenGestureSurface({
-  children,
-  enabled,
-  onOpenExplorer,
-}: CompactExplorerOpenGestureSurfaceProps) {
-  const explorerOpenGesture = useOpenFileExplorerGesture({
-    enabled,
-    onOpen: onOpenExplorer,
-  });
-
-  return (
-    <GestureDetector gesture={explorerOpenGesture} touchAction={COMPACT_WEB_GESTURE_TOUCH_ACTION}>
-      <View style={styles.fill}>{children}</View>
-    </GestureDetector>
-  );
-}
-
-function useActiveCompactExplorerSidebarModel(
-  enabled: boolean,
-): CompactExplorerSidebarHostModel | null {
-  const selection = useActiveWorkspaceSelection();
-  const workspace = useWorkspace(selection?.serverId ?? null, selection?.workspaceId ?? null);
-  const isExplorerActive = useIsMobilePanelActive("file-explorer");
-  const showMobileAgent = usePanelStore((state) => state.showMobileAgent);
-  const client = useHostRuntimeClient(selection?.serverId ?? "");
-  const isConnected = useHostRuntimeIsConnected(selection?.serverId ?? "");
-  const retainedModelRef = useRef<CompactExplorerSidebarHostModel | null>(null);
-  const { checkoutQuery } = useWorkspaceCheckoutStatus({
-    client,
-    isConnected,
-    isRouteFocused: enabled && selection !== null,
-    normalizedServerId: selection?.serverId ?? "",
-    normalizedWorkspaceId: selection?.workspaceId ?? "",
-    workspaceDirectory: workspace?.workspaceDirectory || null,
-  });
-  const resolvedModel = useMemo(
-    () =>
-      resolveCompactExplorerSidebarHostModel({
-        previous: isExplorerActive ? retainedModelRef.current : null,
-        selection,
-        workspace,
-        isGit: checkoutQuery.data?.isGit ?? false,
-      }),
-    [checkoutQuery.data?.isGit, isExplorerActive, selection, workspace],
-  );
-
-  useEffect(() => {
-    if (!selection) {
-      retainedModelRef.current = null;
-      if (enabled && isExplorerActive) {
-        showMobileAgent();
-      }
-      return;
-    }
-    if (!isExplorerActive) {
-      retainedModelRef.current = null;
-      return;
-    }
-    if (resolvedModel) {
-      retainedModelRef.current = resolvedModel;
-    }
-  }, [enabled, isExplorerActive, resolvedModel, selection, showMobileAgent]);
-
-  return selection ? (resolvedModel ?? (isExplorerActive ? retainedModelRef.current : null)) : null;
-}
-
-interface CompactExplorerSidebarHostProps {
-  children: ReactNode;
-  enabled: boolean;
-  presentation: "overlay" | "dock";
-}
-
-export function CompactExplorerSidebarHost({
-  children,
-  enabled,
-  presentation,
-}: CompactExplorerSidebarHostProps) {
-  const model = useActiveCompactExplorerSidebarModel(enabled);
-  const [containerWidth, setContainerWidth] = useState(0);
-  const openCompactFileExplorer = usePanelStore((state) => state.openCompactFileExplorer);
-  const showMobileAgent = usePanelStore((state) => state.showMobileAgent);
-  const openTab = useWorkspaceLayoutStore((state) => state.openTab);
-  const openWorkspaceTabInFocusedPane = useCallback(
-    (workspaceKey: string, target: WorkspaceTabTarget) =>
-      openTab({ workspaceKey, target, intent: "reveal" }),
-    [openTab],
-  );
-  const focusWorkspaceTab = useWorkspaceLayoutStore((state) => state.focusTab);
-
-  const handleOpenExplorer = useCallback(() => {
-    if (!model?.workspaceRoot) {
-      return;
-    }
-    openCompactFileExplorer({
-      serverId: model.serverId,
-      cwd: model.workspaceRoot,
-      isGit: model.isGit,
-    });
-  }, [model, openCompactFileExplorer]);
-
-  const handleOpenFile = useCallback(
-    (filePath: string) => {
-      if (!model) {
-        return;
-      }
-      openWorkspaceFileFromExplorer({
-        filePath,
-        persistenceKey: model.persistenceKey,
-        closeExplorerAfterOpen: presentation === "overlay",
-        showMobileAgent,
-        openWorkspaceTabInFocusedPane,
-        focusWorkspaceTab,
-      });
-    },
-    [focusWorkspaceTab, model, openWorkspaceTabInFocusedPane, presentation, showMobileAgent],
-  );
-
-  const handleContainerLayout = useCallback((event: LayoutChangeEvent) => {
-    const nextWidth = event.nativeEvent.layout.width;
-    setContainerWidth((current) => (current === nextWidth ? current : nextWidth));
-  }, []);
-
-  const explorer =
-    enabled && model ? (
-      <DiffDocumentWorkspaceCacheProvider key={model.persistenceKey}>
-        {presentation === "dock" ? (
-          <NativeExplorerSidebarDock
-            serverId={model.serverId}
-            workspaceId={model.workspaceId}
-            workspaceRoot={model.workspaceRoot}
-            isGit={model.isGit}
-            persistenceKey={model.persistenceKey}
-            containerWidth={containerWidth}
-            onOpenFile={handleOpenFile}
-          />
-        ) : (
-          <CompactExplorerSidebar
-            serverId={model.serverId}
-            workspaceId={model.workspaceId}
-            workspaceRoot={model.workspaceRoot}
-            isGit={model.isGit}
-            onOpenFile={handleOpenFile}
-          />
-        )}
-      </DiffDocumentWorkspaceCacheProvider>
-    ) : null;
-
-  let themedExplorer = explorer;
-  if (isWeb) {
-    themedExplorer = <AppearanceStyleBoundary>{explorer}</AppearanceStyleBoundary>;
-  }
-
-  if (presentation === "dock") {
-    return (
-      <View style={styles.row} onLayout={handleContainerLayout}>
-        <View style={styles.fill}>{children}</View>
-        {themedExplorer}
-      </View>
-    );
-  }
-
-  return (
-    <>
-      <CompactExplorerOpenGestureSurface
-        enabled={enabled && Boolean(model?.workspaceRoot)}
-        onOpenExplorer={handleOpenExplorer}
-      >
-        {children}
-      </CompactExplorerOpenGestureSurface>
-      {themedExplorer}
-    </>
-  );
-}
-
-const styles = {
-  fill: {
-    flex: 1,
-  },
-  row: {
-    flex: 1,
-    flexDirection: "row",
-  },
-} as const;

packages/app/src/components/compact-explorer-sidebar.tsx

@@ -1,574 +0,0 @@
-import { useCallback, useEffect, useMemo, useRef, useState } from "react";
-import { View, Text, Pressable } from "react-native";
-import { Gesture } from "react-native-gesture-handler";
-import Animated, { runOnJS, useAnimatedStyle, useSharedValue } from "react-native-reanimated";
-import { scheduleOnRN } from "react-native-worklets";
-import { useSafeAreaInsets } from "react-native-safe-area-context";
-import { StyleSheet, useUnistyles, withUnistyles } from "react-native-unistyles";
-import { X } from "lucide-react-native";
-import { useTranslation } from "react-i18next";
-import { formatPrTabLabel, PullRequestTabIcon } from "@/git/pull-request-panel";
-import {
-  usePanelStore,
-  selectIsCompactFileExplorerOpen,
-  type ExplorerTab,
-} from "@/stores/panel-store";
-import { useCloseFileExplorerGesture } from "@/mobile-panels/gestures";
-import { useIsMobilePanelActive } from "@/mobile-panels/provider";
-import { MobilePanelOverlay } from "@/mobile-panels/presentation";
-import {
-  HEADER_INNER_HEIGHT,
-  HEADER_INNER_HEIGHT_MOBILE,
-  HEADER_TOP_PADDING_MOBILE,
-  useIsCompactFormFactor,
-} from "@/constants/layout";
-import { ChangesSurface } from "@/git/diff-pane";
-import { changesStateSchema, defaultChangesState, type ChangesState } from "@/panels/changes/state";
-import { FileExplorerPane } from "./file-explorer-pane";
-import { useKeyboardShiftStyle } from "@/keyboard/shift";
-import { shouldUseCompactExplorerKeyboardPadding } from "@/keyboard/shift";
-import { WindowChromeSafeArea } from "@/utils/desktop-window";
-import { TitlebarDragRegion } from "@/components/desktop/titlebar-drag-region";
-import { RetainedPanel, RetainedPanelActivity } from "@/components/retained-panel";
-import { useMountedTabSet } from "@/screens/workspace/use-mounted-tab-set";
-import { usePullRequestPanelAvailability } from "@/panels/pull-request-availability";
-import { PullRequestContent } from "@/panels/pull-request";
-import { useAddFileToChat } from "@/panels/use-add-file-to-chat";
-import { SidebarResizeHandle } from "@/components/sidebar-resize-handle";
-import {
-  SIDEBAR_RESIZE_ACTIVATION_OFFSET,
-  SIDEBAR_RESIZE_FAIL_OFFSET,
-} from "@/components/sidebar-resize-handle-layout";
-import {
-  EXPLORER_TAB_RAIL_INSET,
-  explorerSidebarCloseButtonLayout,
-  resolveExplorerSidebarWidth,
-} from "@/components/explorer-sidebar-layout";
-import { ToolbarButton } from "@/components/ui/pane-content-toolbar";
-import { mutedIconColorMapping } from "@/components/ui/icon-button-chrome";
-import { useWorkspaceLayoutStore } from "@/stores/workspace-layout-store";
-
-const ThemedX = withUnistyles(X);
-
-function logExplorerSidebar(_event: string, _details: Record<string, unknown>): void {}
-
-interface ExplorerSidebarProps {
-  serverId: string;
-  workspaceId?: string | null;
-  workspaceRoot: string;
-  isGit: boolean;
-  onOpenFile?: (filePath: string) => void;
-}
-
-interface ExplorerSidebarSharedState {
-  explorerTab: ExplorerTab;
-  handleTabPress: (tab: ExplorerTab) => void;
-}
-
-function useExplorerSidebarSharedState({
-  serverId,
-  workspaceRoot,
-  isGit,
-}: Pick<ExplorerSidebarProps, "serverId" | "workspaceRoot" | "isGit">): ExplorerSidebarSharedState {
-  const explorerTab = usePanelStore((state) => state.explorerTab);
-  const setExplorerTabForCheckout = usePanelStore((state) => state.setExplorerTabForCheckout);
-  const handleTabPress = useCallback(
-    (tab: ExplorerTab) => {
-      setExplorerTabForCheckout({ serverId, cwd: workspaceRoot, isGit, tab });
-    },
-    [isGit, serverId, setExplorerTabForCheckout, workspaceRoot],
-  );
-
-  return { explorerTab, handleTabPress };
-}
-
-export function CompactExplorerSidebar({
-  serverId,
-  workspaceId,
-  workspaceRoot,
-  isGit,
-  onOpenFile,
-}: ExplorerSidebarProps) {
-  const { theme } = useUnistyles();
-  const insets = useSafeAreaInsets();
-  const isActive = useIsMobilePanelActive("file-explorer");
-  const showMobileAgent = usePanelStore((state) => state.showMobileAgent);
-  const { explorerTab, handleTabPress } = useExplorerSidebarSharedState({
-    serverId,
-    workspaceRoot,
-    isGit,
-  });
-  const usePanelKeyboardPadding = shouldUseCompactExplorerKeyboardPadding({ isGit, explorerTab });
-  const { style: mobileKeyboardInsetStyle } = useKeyboardShiftStyle({
-    mode: "padding",
-    enabled: usePanelKeyboardPadding,
-  });
-  const { gesture: closeGesture } = useCloseFileExplorerGesture();
-
-  const handleClose = useCallback(
-    (reason: string) => {
-      logExplorerSidebar("handleClose", {
-        reason,
-        isOpen: isActive,
-      });
-      showMobileAgent();
-    },
-    [isActive, showMobileAgent],
-  );
-
-  const handleHeaderClose = useCallback(() => handleClose("header-close-button"), [handleClose]);
-
-  const mobileSidebarStyle = useMemo(
-    () => [
-      {
-        paddingTop: insets.top + HEADER_TOP_PADDING_MOBILE,
-        paddingBottom: usePanelKeyboardPadding ? 0 : insets.bottom,
-        backgroundColor: theme.colors.surfaceSidebar,
-      },
-      mobileKeyboardInsetStyle,
-    ],
-    [
-      insets.bottom,
-      insets.top,
-      mobileKeyboardInsetStyle,
-      theme.colors.surfaceSidebar,
-      usePanelKeyboardPadding,
-    ],
-  );
-
-  return (
-    <RetainedPanelActivity active={isActive}>
-      <MobilePanelOverlay
-        panel="file-explorer"
-        closeGesture={closeGesture}
-        panelStyle={mobileSidebarStyle}
-      >
-        <ExplorerSidebarContent
-          activeTab={explorerTab}
-          onTabPress={handleTabPress}
-          onClose={handleHeaderClose}
-          serverId={serverId}
-          workspaceId={workspaceId}
-          workspaceRoot={workspaceRoot}
-          isGit={isGit}
-          isOpen={isActive}
-          onOpenFile={onOpenFile}
-        />
-      </MobilePanelOverlay>
-    </RetainedPanelActivity>
-  );
-}
-
-interface NativeExplorerSidebarDockProps extends ExplorerSidebarProps {
-  persistenceKey: string;
-  containerWidth: number;
-}
-
-export function NativeExplorerSidebarDock({
-  serverId,
-  workspaceId,
-  workspaceRoot,
-  isGit,
-  onOpenFile,
-  persistenceKey,
-  containerWidth,
-}: NativeExplorerSidebarDockProps) {
-  const { theme } = useUnistyles();
-  const insets = useSafeAreaInsets();
-  const isOpen = usePanelStore(selectIsCompactFileExplorerOpen);
-  const showMobileAgent = usePanelStore((state) => state.showMobileAgent);
-  const storedWidth = useWorkspaceLayoutStore(
-    (state) => state.explorerSidebarWidthByWorkspace[persistenceKey],
-  );
-  const resizeExplorerSidebar = useWorkspaceLayoutStore((state) => state.resizeExplorerSidebar);
-  const visibleWidth = resolveExplorerSidebarWidth({
-    requestedWidth: storedWidth,
-    containerWidth,
-  });
-  const resizeWidth = useSharedValue(visibleWidth);
-  const startWidthRef = useRef(visibleWidth);
-  const [resizePressed, setResizePressed] = useState(false);
-  const { explorerTab, handleTabPress } = useExplorerSidebarSharedState({
-    serverId,
-    workspaceRoot,
-    isGit,
-  });
-
-  useEffect(() => {
-    resizeWidth.value = visibleWidth;
-  }, [resizeWidth, visibleWidth]);
-
-  const showResizeGrip = useCallback(() => setResizePressed(true), []);
-  const hideResizeGrip = useCallback(() => setResizePressed(false), []);
-  const commitWidth = useCallback(
-    (width: number) => resizeExplorerSidebar(persistenceKey, width),
-    [persistenceKey, resizeExplorerSidebar],
-  );
-  const resizeGesture = useMemo(
-    () =>
-      Gesture.Pan()
-        .enabled(true)
-        .hitSlop({ left: 8, right: 8, top: 0, bottom: 0 })
-        .onBegin(() => scheduleOnRN(showResizeGrip))
-        .activeOffsetX([-SIDEBAR_RESIZE_ACTIVATION_OFFSET, SIDEBAR_RESIZE_ACTIVATION_OFFSET])
-        .failOffsetY([-SIDEBAR_RESIZE_FAIL_OFFSET, SIDEBAR_RESIZE_FAIL_OFFSET])
-        .onStart((event) => {
-          startWidthRef.current = visibleWidth + event.translationX;
-          resizeWidth.value = visibleWidth;
-        })
-        .onUpdate((event) => {
-          resizeWidth.value = resolveExplorerSidebarWidth({
-            requestedWidth: startWidthRef.current - event.translationX,
-            containerWidth,
-          });
-        })
-        .onEnd(() => runOnJS(commitWidth)(resizeWidth.value))
-        .onFinalize(() => scheduleOnRN(hideResizeGrip)),
-    [commitWidth, containerWidth, hideResizeGrip, resizeWidth, showResizeGrip, visibleWidth],
-  );
-  const animatedWidthStyle = useAnimatedStyle(() => ({ width: resizeWidth.value }));
-  const dockStyle = useMemo(
-    () => [
-      styles.nativeDock,
-      {
-        display: isOpen ? ("flex" as const) : ("none" as const),
-        paddingTop: insets.top + HEADER_TOP_PADDING_MOBILE,
-        backgroundColor: theme.colors.surfaceSidebar,
-      },
-      animatedWidthStyle,
-    ],
-    [animatedWidthStyle, insets.top, isOpen, theme.colors.surfaceSidebar],
-  );
-  const dockContentStyle = useMemo(
-    () => [styles.nativeDockContent, { borderLeftColor: theme.colors.border }],
-    [theme.colors.border],
-  );
-
-  return (
-    <RetainedPanelActivity active={isOpen}>
-      <Animated.View style={dockStyle} testID="native-explorer-sidebar-dock">
-        <View style={dockContentStyle}>
-          <SidebarResizeHandle
-            edge="left"
-            gesture={resizeGesture}
-            pressed={resizePressed}
-            testID="native-explorer-sidebar-resize-handle"
-          />
-          <ExplorerSidebarContent
-            activeTab={explorerTab}
-            onTabPress={handleTabPress}
-            onClose={showMobileAgent}
-            serverId={serverId}
-            workspaceId={workspaceId}
-            workspaceRoot={workspaceRoot}
-            isGit={isGit}
-            isOpen={isOpen}
-            onOpenFile={onOpenFile}
-          />
-        </View>
-      </Animated.View>
-    </RetainedPanelActivity>
-  );
-}
-
-interface ExplorerTabButtonProps {
-  tab: ExplorerTab;
-  active: boolean;
-  label?: string;
-  onTabPress: (tab: ExplorerTab) => void;
-  testID: string;
-  children?: React.ReactNode;
-}
-
-function ExplorerTabButton({
-  tab,
-  active,
-  label,
-  onTabPress,
-  testID,
-  children,
-}: ExplorerTabButtonProps) {
-  const isCompact = useIsCompactFormFactor();
-  const handlePress = useCallback(() => onTabPress(tab), [onTabPress, tab]);
-  const tabStyle = useMemo(
-    () => [styles.tab(isCompact), active && styles.tabActive],
-    [active, isCompact],
-  );
-  const tabTextStyle = useMemo(() => [styles.tabText, active && styles.tabTextActive], [active]);
-  return (
-    <Pressable testID={testID} style={tabStyle} onPress={handlePress}>
-      {children}
-      {label !== undefined ? <Text style={tabTextStyle}>{label}</Text> : null}
-    </Pressable>
-  );
-}
-
-interface SidebarContentProps {
-  activeTab: ExplorerTab;
-  onTabPress: (tab: ExplorerTab) => void;
-  onClose: () => void;
-  serverId: string;
-  workspaceId?: string | null;
-  workspaceRoot: string;
-  isGit: boolean;
-  isOpen: boolean;
-  onOpenFile?: (filePath: string) => void;
-}
-
-function ExplorerSidebarContent({
-  activeTab,
-  onTabPress,
-  onClose,
-  serverId,
-  workspaceId,
-  workspaceRoot,
-  isGit,
-  isOpen,
-  onOpenFile,
-}: SidebarContentProps) {
-  const { theme } = useUnistyles();
-  const { t } = useTranslation();
-  const isCompact = useIsCompactFormFactor();
-  const closeButtonLayout = explorerSidebarCloseButtonLayout(isCompact);
-  const closeButtonStyle = useMemo(
-    () => ({ width: closeButtonLayout.size, height: closeButtonLayout.size }),
-    [closeButtonLayout.size],
-  );
-  // The close glyph shares the trailing rail with the toolbar rows below it.
-  const headerRightSectionStyle = useMemo(
-    () => [styles.headerRightSection, { paddingRight: closeButtonLayout.trailingPadding }],
-    [closeButtonLayout.trailingPadding],
-  );
-  const { prPane, showPullRequest: showPrTab } = usePullRequestPanelAvailability({
-    serverId,
-    cwd: workspaceRoot,
-    isGit,
-    requested: activeTab === "pr",
-    enabled: isOpen,
-    timelineEnabled: activeTab === "pr",
-  });
-  const requestedTab: ExplorerTab =
-    !isGit && (activeTab === "changes" || activeTab === "pr") ? "files" : activeTab;
-  const resolvedTab: ExplorerTab = requestedTab === "pr" && !showPrTab ? "changes" : requestedTab;
-  const prTabLabel = formatPrTabLabel(prPane.prNumber);
-  const availableTabs = useMemo<ExplorerTab[]>(() => {
-    const tabs: ExplorerTab[] = isGit ? ["changes", "files"] : ["files"];
-    if (isGit && showPrTab) tabs.push("pr");
-    return tabs;
-  }, [isGit, showPrTab]);
-  const { mountedTabIds } = useMountedTabSet({
-    activeTabId: resolvedTab,
-    allTabIds: availableTabs,
-    cap: availableTabs.length,
-  });
-
-  return (
-    <View style={styles.sidebarContent} pointerEvents="auto">
-      {/* Header with tabs and close button */}
-      <WindowChromeSafeArea placement="inline" style={styles.header} testID="explorer-header">
-        <TitlebarDragRegion />
-        <View style={styles.tabsContainer(isCompact)}>
-          {isGit && (
-            <ExplorerTabButton
-              tab="changes"
-              active={resolvedTab === "changes"}
-              label={t("workspace.tabs.explorerSidebar.changes")}
-              onTabPress={onTabPress}
-              testID="explorer-tab-changes"
-            />
-          )}
-          <ExplorerTabButton
-            tab="files"
-            active={resolvedTab === "files"}
-            label={t("workspace.tabs.explorerSidebar.files")}
-            onTabPress={onTabPress}
-            testID="explorer-tab-files"
-          />
-          {isGit && showPrTab && (
-            <ExplorerTabButton
-              tab="pr"
-              active={resolvedTab === "pr"}
-              label={prTabLabel}
-              onTabPress={onTabPress}
-              testID="explorer-tab-pr"
-            >
-              <PullRequestTabIcon
-                forge={prPane.forge}
-                size={13}
-                color={
-                  resolvedTab === "pr" ? theme.colors.foreground : theme.colors.foregroundMuted
-                }
-              />
-            </ExplorerTabButton>
-          )}
-        </View>
-        <View style={headerRightSectionStyle}>
-          <ToolbarButton
-            compact={isCompact}
-            style={closeButtonStyle}
-            hitSlop={closeButtonLayout.hitSlop}
-            label={t("workspace.tabs.explorerSidebar.close")}
-            onPress={onClose}
-            testID="explorer-close"
-            nativeID="explorer-close"
-          >
-            <ThemedX size={closeButtonLayout.iconSize} uniProps={mutedIconColorMapping} />
-          </ToolbarButton>
-        </View>
-      </WindowChromeSafeArea>
-
-      {/* Content based on active tab */}
-      <View style={styles.contentArea} testID="explorer-content-area">
-        {mountedTabIds.has("changes") ? (
-          <RetainedPanel active={resolvedTab === "changes"}>
-            <ChangedFilesPane
-              serverId={serverId}
-              workspaceId={workspaceId}
-              workspaceRoot={workspaceRoot}
-              isOpen={isOpen}
-              onOpenFile={onOpenFile}
-            />
-          </RetainedPanel>
-        ) : null}
-        {mountedTabIds.has("files") ? (
-          <RetainedPanel active={resolvedTab === "files"}>
-            <FilesPane
-              serverId={serverId}
-              workspaceId={workspaceId}
-              workspaceRoot={workspaceRoot}
-              onOpenFile={onOpenFile}
-            />
-          </RetainedPanel>
-        ) : null}
-        {mountedTabIds.has("pr") ? (
-          <RetainedPanel active={resolvedTab === "pr"}>
-            <PrTabContent
-              serverId={serverId}
-              workspaceId={workspaceId}
-              cwd={workspaceRoot}
-              prPane={prPane}
-            />
-          </RetainedPanel>
-        ) : null}
-      </View>
-    </View>
-  );
-}
-
-function ChangedFilesPane({
-  serverId,
-  workspaceId,
-  workspaceRoot,
-  isOpen,
-  onOpenFile,
-}: Pick<
-  SidebarContentProps,
-  "serverId" | "workspaceId" | "workspaceRoot" | "isOpen" | "onOpenFile"
->) {
-  const { addFile, canAddToChat } = useAddFileToChat({ serverId, workspaceId });
-  const [changesState, setChangesState] = useState<ChangesState>(() =>
-    changesStateSchema.parse(defaultChangesState),
-  );
-  return (
-    <ChangesSurface
-      serverId={serverId}
-      workspaceId={workspaceId}
-      cwd={workspaceRoot}
-      enabled={isOpen}
-      onOpenFile={onOpenFile}
-      onAddToChat={canAddToChat ? addFile : undefined}
-      state={changesState}
-      onStateChange={setChangesState}
-    />
-  );
-}
-
-function FilesPane({
-  serverId,
-  workspaceId,
-  workspaceRoot,
-  onOpenFile,
-}: Pick<SidebarContentProps, "serverId" | "workspaceId" | "workspaceRoot" | "onOpenFile">) {
-  const { addFile, canAddToChat } = useAddFileToChat({ serverId, workspaceId });
-  return (
-    <FileExplorerPane
-      serverId={serverId}
-      workspaceId={workspaceId}
-      workspaceRoot={workspaceRoot}
-      onOpenFile={onOpenFile}
-      onAddToChat={canAddToChat ? addFile : undefined}
-    />
-  );
-}
-
-const PrTabContent = PullRequestContent;
-
-const styles = StyleSheet.create((theme) => ({
-  nativeDock: {
-    position: "relative",
-    height: "100%",
-    minHeight: 0,
-    overflow: "hidden",
-  },
-  nativeDockContent: {
-    position: "relative",
-    flex: 1,
-    minHeight: 0,
-    borderLeftWidth: 1,
-  },
-  sidebarContent: {
-    flex: 1,
-    minHeight: 0,
-    overflow: "hidden",
-  },
-  header: {
-    position: "relative",
-    height: {
-      xs: HEADER_INNER_HEIGHT_MOBILE,
-      md: HEADER_INNER_HEIGHT,
-    },
-    flexDirection: "row",
-    alignItems: "center",
-    justifyContent: "space-between",
-    borderBottomWidth: 1,
-    borderBottomColor: theme.colors.border,
-  },
-  tabsContainer: (isCompact: boolean) => ({
-    flexDirection: "row",
-    gap: theme.spacing[1],
-    // With the tab's own horizontal padding this puts the label on the pane's
-    // leading rail, the same way the desktop tab rail does.
-    paddingLeft: isCompact ? EXPLORER_TAB_RAIL_INSET : theme.spacing[2],
-  }),
-  tab: (isCompact: boolean) => ({
-    flexDirection: "row",
-    alignItems: "center",
-    gap: theme.spacing[2],
-    paddingVertical: theme.spacing[2],
-    paddingHorizontal: isCompact ? theme.spacing[2] : theme.spacing[3],
-    borderRadius: theme.borderRadius.md,
-  }),
-  tabActive: {
-    backgroundColor: theme.colors.surfaceSidebarHover,
-  },
-  tabText: {
-    fontSize: theme.fontSize.base,
-    fontWeight: theme.fontWeight.normal,
-    color: theme.colors.foregroundMuted,
-  },
-  tabTextActive: {
-    color: theme.colors.foreground,
-  },
-  tabTextMuted: {
-    opacity: 0.8,
-  },
-  headerRightSection: {
-    flexDirection: "row",
-    alignItems: "center",
-    gap: theme.spacing[2],
-  },
-  contentArea: {
-    flex: 1,
-    minHeight: 0,
-  },
-}));

packages/app/src/components/desktop-sidebar-layout.test.ts

@@ -101,3 +101,25 @@ describe("desktop sidebar layout", () => {
     ).toBe(true);
   });
 });
+
+it("reserves room for Explorer and the workspace before showing app navigation", () => {
+  const contentMinimumWidth = resolveDesktopAppContentMinimum({
+    isSettingsRoute: false,
+    explorerVisible: true,
+  });
+  expect(contentMinimumWidth).toBe(600);
+  expect(
+    canDesktopAppSidebarShare({
+      contentMinimumWidth,
+      requestedSidebarWidth: 320,
+      viewportWidth: 744,
+    }),
+  ).toBe(false);
+  expect(
+    canDesktopAppSidebarShare({
+      contentMinimumWidth,
+      requestedSidebarWidth: 320,
+      viewportWidth: 951,
+    }),
+  ).toBe(true);
+});

packages/app/src/components/desktop-sidebar-layout.ts

@@ -1,3 +1,4 @@
+import { EXPLORER_WORKSPACE_MIN_WIDTH } from "@/components/explorer-sidebar-layout";
 import { SETTINGS_DESKTOP_SPLIT_MIN_WIDTH } from "@/constants/layout";
 import { MAX_SIDEBAR_WIDTH, MIN_SIDEBAR_WIDTH } from "@/stores/panel-store";
 
@@ -62,8 +63,12 @@ export function resolveDesktopSidebarWidth(input: {
   });
 }
 
-export function resolveDesktopAppContentMinimum(input: { isSettingsRoute: boolean }): number {
-  return input.isSettingsRoute ? SETTINGS_DESKTOP_SPLIT_MIN_WIDTH : 0;
+export function resolveDesktopAppContentMinimum(input: {
+  isSettingsRoute: boolean;
+  explorerVisible?: boolean;
+}): number {
+  if (input.isSettingsRoute) return SETTINGS_DESKTOP_SPLIT_MIN_WIDTH;
+  return input.explorerVisible ? EXPLORER_WORKSPACE_MIN_WIDTH : 0;
 }
 
 export function canDesktopAppSidebarShare(input: {

packages/app/src/components/explorer-sidebar-layout.test.ts

@@ -1,6 +1,5 @@
 import { describe, expect, it } from "vitest";
 import {
-  explorerSidebarCloseButtonLayout,
   resolveExplorerSidebarDockSizes,
   resolveExplorerSidebarWidth,
 } from "@/components/explorer-sidebar-layout";
@@ -17,24 +16,7 @@ describe("Explorer sidebar layout", () => {
   it("has no fixed maximum while preserving room for the workspace body", () => {
     expect(resolveExplorerSidebarWidth({ requestedWidth: 100, containerWidth: 1200 })).toBe(240);
     expect(resolveExplorerSidebarWidth({ requestedWidth: 900, containerWidth: 1600 })).toBe(900);
-    expect(resolveExplorerSidebarWidth({ requestedWidth: 900, containerWidth: 1200 })).toBe(800);
-    expect(resolveExplorerSidebarWidth({ requestedWidth: 600, containerWidth: 750 })).toBe(350);
-  });
-});
-
-describe("Explorer close action", () => {
-  it("preserves the wide-native touch target and glyph rail", () => {
-    const layout = explorerSidebarCloseButtonLayout(false);
-    expect(layout.size).toBe(34);
-    expect(layout.iconSize).toBe(18);
-    expect(layout.size + layout.hitSlop * 2).toBe(50);
-    expect(layout.trailingPadding + (layout.size - layout.iconSize) / 2).toBe(16);
-  });
-
-  it("keeps the compact close glyph on the pane rail", () => {
-    const layout = explorerSidebarCloseButtonLayout(true);
-    expect(layout.size).toBe(32);
-    expect(layout.iconSize).toBe(18);
-    expect(layout.trailingPadding + (layout.size - layout.iconSize) / 2).toBe(8);
+    expect(resolveExplorerSidebarWidth({ requestedWidth: 900, containerWidth: 1200 })).toBe(840);
+    expect(resolveExplorerSidebarWidth({ requestedWidth: 600, containerWidth: 750 })).toBe(390);
   });
 });

packages/app/src/components/explorer-sidebar-layout.ts

@@ -1,36 +1,13 @@
-import {
-  paneContentToolbarIconSize,
-  paneContentToolbarTrailingPadding,
-} from "@/components/ui/pane-content-toolbar";
-import { smallIconButtonChromeFrameSize } from "@/components/ui/icon-button-chrome";
-
-export function explorerSidebarCloseButtonLayout(compact: boolean) {
-  // The inline native dock retains its padded close action and touch slop.
-  if (!compact) {
-    return { size: 34, iconSize: 18, hitSlop: 8, trailingPadding: 8 };
-  }
-  return {
-    size: smallIconButtonChromeFrameSize(compact),
-    iconSize: paneContentToolbarIconSize(compact),
-    hitSlop: 0,
-    trailingPadding: paneContentToolbarTrailingPadding(compact, "glyph"),
-  };
-}
-
-/**
- * Outer inset of an Explorer tab rail. With each tab's own horizontal padding it puts
- * the tab label on the pane's shared leading rail (`treeRowPaddingLeft(0)`).
- */
-export const EXPLORER_TAB_RAIL_INSET = 4;
-
 const DEFAULT_EXPLORER_SIDEBAR_WIDTH = 320;
 const MIN_EXPLORER_SIDEBAR_WIDTH = 240;
-const MIN_WORKSPACE_BODY_WIDTH = 400;
+const MIN_WORKSPACE_BODY_WIDTH = 360;
+export const EXPLORER_WORKSPACE_MIN_WIDTH = MIN_EXPLORER_SIDEBAR_WIDTH + MIN_WORKSPACE_BODY_WIDTH;
 
 export function resolveExplorerSidebarWidth(input: {
   requestedWidth?: number;
   containerWidth: number;
 }): number {
+  "worklet";
   const requestedWidth = input.requestedWidth ?? DEFAULT_EXPLORER_SIDEBAR_WIDTH;
   const maximumVisibleWidth =
     input.containerWidth > 0

packages/app/src/components/file-drop/file-drop-backdrop.tsx

@@ -46,7 +46,7 @@ export function FileDropBackdrop() {
 
 const positionStyles = RNStyleSheet.create({
   overlay: {
-    ...RNStyleSheet.absoluteFillObject,
+    ...RNStyleSheet.absoluteFill,
     alignItems: "center",
     justifyContent: "center",
     zIndex: 1000,
@@ -55,7 +55,7 @@ const positionStyles = RNStyleSheet.create({
 
 const styles = StyleSheet.create((theme) => ({
   backdrop: {
-    ...StyleSheet.absoluteFillObject,
+    ...StyleSheet.absoluteFill,
     backgroundColor: theme.colors.surface0,
     opacity: 0.7,
   },

packages/app/src/components/headers/compact-header.tsx

@@ -52,8 +52,15 @@ export function CompactHeader({
 }: CompactHeaderProps) {
   const insets = useSafeAreaInsets();
   const rootStyle = useMemo(
-    () => [styles.root, { paddingTop: insets.top + HEADER_TOP_PADDING_MOBILE }],
-    [insets.top],
+    () => [
+      styles.root,
+      {
+        paddingTop: insets.top + HEADER_TOP_PADDING_MOBILE,
+        marginLeft: insets.left,
+        marginRight: insets.right,
+      },
+    ],
+    [insets.top, insets.left, insets.right],
   );
 
   return (

packages/app/src/components/left-sidebar.tsx

@@ -679,7 +679,9 @@ function DesktopSidebar({
   const hasActiveHostFilter = useSidebarViewStore((state) => state.hostFilters.length > 0);
   const sidebarWidth = usePanelStore((state) => state.sidebarWidth);
   const setSidebarWidth = usePanelStore((state) => state.setSidebarWidth);
-  const { width: viewportWidth } = useWindowDimensions();
+  const { width: windowWidth } = useWindowDimensions();
+  const insets = useSafeAreaInsets();
+  const viewportWidth = windowWidth - insets.left - insets.right;
   const visibleSidebarWidth = resolveDesktopSidebarWidth({
     requestedWidth: sidebarWidth,
     viewportWidth,

packages/app/src/components/sidebar-workspace-list.tsx

@@ -2761,7 +2761,7 @@ const styles = StyleSheet.create((theme) => ({
     justifyContent: "center",
   },
   workspaceArchivingOverlay: {
-    ...StyleSheet.absoluteFillObject,
+    ...StyleSheet.absoluteFill,
     borderRadius: theme.borderRadius.lg,
     backgroundColor: `${theme.colors.surface0}cc`,
     alignItems: "center",

packages/app/src/components/split-container.tsx

@@ -1,3 +1,4 @@
+import { useWorkspaceTabDrag } from "./workspace-tab-drag-context";
 import {
   Fragment,
   memo,
@@ -11,35 +12,14 @@ import {
   type SetStateAction,
 } from "react";
 import { useStableEvent } from "@/hooks/use-stable-event";
-import {
-  DndContext,
-  DragOverlay,
-  KeyboardSensor,
-  PointerSensor,
-  closestCenter,
-  pointerWithin,
-  useSensor,
-  useSensors,
-  type CollisionDetection,
-  type DragEndEvent,
-  type DragMoveEvent,
-  type DragOverEvent,
-  type DragStartEvent,
-} from "@dnd-kit/core";
-import { arrayMove, sortableKeyboardCoordinates } from "@dnd-kit/sortable";
-import { View, Text, type LayoutChangeEvent } from "react-native";
+import { View, type LayoutChangeEvent } from "react-native";
 import Animated, {
   useAnimatedStyle,
   useSharedValue,
   type SharedValue,
 } from "react-native-reanimated";
-import { useTranslation } from "react-i18next";
-import { StyleSheet, useUnistyles } from "react-native-unistyles";
+import { StyleSheet } from "react-native-unistyles";
 import { ResizeHandle } from "@/components/resize-handle";
-import {
-  resolveExplorerSidebarDockSizes,
-  resolveExplorerSidebarWidth,
-} from "@/components/explorer-sidebar-layout";
 import { RetainedPanel } from "@/components/retained-panel";
 import {
   hasMultipleVisiblePanes,
@@ -48,41 +28,26 @@ import {
 } from "@/components/split-container-focus";
 import { shouldFocusPaneFromEventTarget } from "@/components/split-container-pane-focus";
 import {
-  removeWindowChromeCorner,
   WindowChromeRegion,
   WindowChromeSafeArea,
   useWindowChromeCorners,
+  removeWindowChromeCorner,
   type WindowChromeCorners,
 } from "@/utils/desktop-window";
 import { TitlebarDragRegion } from "@/components/desktop/titlebar-drag-region";
-import {
-  computeTabDropPreview,
-  type TabDropPreview,
-} from "@/components/split-container-tab-drop-preview";
-import {
-  SplitDropZone,
-  resolveSplitDropPosition,
-  type SplitDropZoneHover,
-} from "@/components/split-drop-zone";
-import {
-  deriveWorkspacePaneState,
-  getWorkspacePaneDescriptors,
-} from "@/screens/workspace/workspace-pane-state";
+import { type TabDropPreview } from "@/components/split-container-tab-drop-preview";
+import { SplitDropZone, type SplitDropZoneHover } from "@/components/split-drop-zone";
+import { deriveWorkspacePaneState } from "@/screens/workspace/workspace-pane-state";
 import type { WorkspacePaneContentModel } from "@/screens/workspace/workspace-pane-content";
 import { WorkspacePanelHost } from "@/screens/workspace/workspace-panel-host";
 import {
   WorkspaceDesktopTabsRow,
   type WorkspaceDesktopTabRowItem,
 } from "@/screens/workspace/workspace-desktop-tabs-row";
-import { ExplorerSidebarDock } from "@/screens/workspace/explorer-sidebar";
-import {
-  WorkspaceTabPresentationResolver,
-  WorkspaceTabIcon,
-} from "@/screens/workspace/workspace-tab-presentation";
 import type { WorkspaceTabDescriptor } from "@/screens/workspace/workspace-tabs-types";
 import {
+  collectAllPanes,
   createDefaultLayout,
-  findPaneById,
   useWorkspaceLayoutStore,
   type SplitNode,
   type SplitPane,
@@ -90,14 +55,11 @@ import {
 } from "@/stores/workspace-layout-store";
 import type { WorkspaceTab } from "@/workspace-tabs/model";
 import { recordRenderProfileReasons, RenderProfile } from "@/utils/render-profiler";
-import { inlineUnistylesStyle } from "@/styles/unistyles-inline-style";
 import { isNative } from "@/constants/platform";
-import { panelTargetSupportsHost } from "@/plugins/workspace-panels/locations";
 
 interface SplitContainerProps {
   layout: WorkspaceLayout;
   renderMainHeader?: () => ReactNode;
-  renderExplorerSidebarHeaderAction?: () => ReactNode;
   workspaceKey: string;
   normalizedServerId: string;
   normalizedWorkspaceId: string;
@@ -140,41 +102,6 @@ interface SplitContainerProps {
   onExitFocusMode: () => void;
 }
 
-interface WorkspaceTabDragData {
-  kind: "workspace-tab";
-  paneId: string;
-  tabId: string;
-}
-
-interface SplitPaneDropData {
-  kind: "split-pane-drop";
-  paneId: string;
-}
-
-const EMPTY_SPLIT_NODES: SplitNode[] = [];
-const EMPTY_SPLIT_SIZES: number[] = [];
-const EXPLORER_SIDEBAR_RESIZE_GROUP_ID = "explorer-sidebar";
-
-function isWorkspaceTabDragData(data: unknown): data is WorkspaceTabDragData {
-  return typeof data === "object" && data !== null && Reflect.get(data, "kind") === "workspace-tab";
-}
-
-function isSplitPaneDropData(data: unknown): data is SplitPaneDropData {
-  return (
-    typeof data === "object" && data !== null && Reflect.get(data, "kind") === "split-pane-drop"
-  );
-}
-
-function asWorkspaceTabDragData(data: unknown): WorkspaceTabDragData | undefined {
-  return isWorkspaceTabDragData(data) ? data : undefined;
-}
-
-function asDragOverData(data: unknown): WorkspaceTabDragData | SplitPaneDropData | undefined {
-  if (isWorkspaceTabDragData(data)) return data;
-  if (isSplitPaneDropData(data)) return data;
-  return undefined;
-}
-
 interface SplitNodeViewProps extends Omit<
   SplitContainerProps,
   "layout" | "onMoveTabToPane" | "onSelectTabInPane"
@@ -212,105 +139,12 @@ interface SplitPaneViewProps extends Omit<
   tabDropPreview: TabDropPreview | null;
 }
 
-interface DragMoveRects {
-  translatedRect: { left: number; top: number; width: number; height: number };
-  overRect: { left: number; top: number; width: number; height: number };
-}
-
-function resolveDragMoveRects(
-  event: Pick<DragMoveEvent, "active" | "over"> | Pick<DragOverEvent, "active" | "over">,
-): DragMoveRects | null {
-  const translatedRect = event.active.rect.current.translated;
-  const overRect = event.over?.rect;
-  if (!translatedRect || !overRect || overRect.width <= 0 || overRect.height <= 0) {
-    return null;
-  }
-  return { translatedRect, overRect };
-}
-
-function computeTabOverDropPreview(input: {
-  activeData: WorkspaceTabDragData;
-  overData: WorkspaceTabDragData;
-  rects: DragMoveRects;
-  panesById: Map<string, SplitPane>;
-  uiTabs: WorkspaceTab[];
-}): TabDropPreview | null {
-  const { activeData, overData, rects, panesById, uiTabs } = input;
-  const targetPane = panesById.get(overData.paneId) ?? null;
-  if (!targetPane) {
-    return null;
-  }
-  const targetTabs = getWorkspacePaneDescriptors({ pane: targetPane, tabs: uiTabs });
-  return computeTabDropPreview({
-    activePaneId: activeData.paneId,
-    activeTabId: activeData.tabId,
-    overPaneId: overData.paneId,
-    overTabId: overData.tabId,
-    targetTabs,
-    activeRect: {
-      left: rects.translatedRect.left,
-      width: rects.translatedRect.width,
-    },
-    overRect: {
-      left: rects.overRect.left,
-      width: rects.overRect.width,
-    },
-  });
-}
-
-function computePaneOverDropPreview(input: {
-  overData: SplitPaneDropData;
-  rects: DragMoveRects;
-}): SplitDropZoneHover | null {
-  const { overData, rects } = input;
-  const centerX = rects.translatedRect.left + rects.translatedRect.width / 2;
-  const centerY = rects.translatedRect.top + rects.translatedRect.height / 2;
-  const relativeX = centerX - rects.overRect.left;
-  const relativeY = centerY - rects.overRect.top;
-  if (
-    Number.isNaN(relativeX) ||
-    Number.isNaN(relativeY) ||
-    relativeX < 0 ||
-    relativeX > rects.overRect.width ||
-    relativeY < 0 ||
-    relativeY > rects.overRect.height
-  ) {
-    return null;
-  }
-  return {
-    paneId: overData.paneId,
-    position: resolveSplitDropPosition({
-      width: rects.overRect.width,
-      height: rects.overRect.height,
-      x: relativeX,
-      y: relativeY,
-    }),
-  };
-}
-
-const dropCollisionDetection: CollisionDetection = (args) => {
-  const pointerHits = pointerWithin(args);
-  const tabHits = pointerHits.filter(
-    (entry) => entry.data?.droppableContainer.data.current?.kind === "workspace-tab",
-  );
-  if (tabHits.length > 0) {
-    return tabHits;
-  }
-
-  const paneHits = pointerHits.filter(
-    (entry) => entry.data?.droppableContainer.data.current?.kind === "split-pane-drop",
-  );
-  if (paneHits.length > 0) {
-    return paneHits;
-  }
-
-  return closestCenter(args);
-};
+const EMPTY_SPLIT_NODES: SplitNode[] = [];
+const EMPTY_SPLIT_SIZES: number[] = [];
 
 export function SplitContainer({
   layout,
   renderMainHeader,
-  renderExplorerSidebarHeaderAction,
   workspaceKey,
   normalizedServerId,
   normalizedWorkspaceId,
@@ -335,8 +169,6 @@ export function SplitContainer({
   onFocusPane,
   onSplitPane,
   onSplitPaneEmpty,
-  onMoveTabToPane,
-  onSelectTabInPane,
   onResizeSplit,
   onReorderTabsInPane,
   focusModeEnabled,
@@ -344,9 +176,7 @@ export function SplitContainer({
 }: SplitContainerProps) {
   const inheritedWindowChromeCorners = useWindowChromeCorners();
   const windowChromeCorners = focusModeEnabled ? inheritedWindowChromeCorners : "none";
-  const [activeDragTabId, setActiveDragTabId] = useState<string | null>(null);
-  const [dropPreview, setDropPreview] = useState<SplitDropZoneHover | null>(null);
-  const [tabDropPreview, setTabDropPreview] = useState<TabDropPreview | null>(null);
+  const { activeDragTabId, dropPreview, tabDropPreview } = useWorkspaceTabDrag();
   const [maximizedPane, setMaximizedPane] = useState<{
     workspaceKey: string;
     paneId: string;
@@ -357,22 +187,6 @@ export function SplitContainer({
     (state) => state.explorerSidebarPaneIdByWorkspace[workspaceKey] ?? null,
   );
 
-  const sensors = useSensors(
-    useSensor(PointerSensor, {
-      activationConstraint: {
-        distance: 8,
-      },
-    }),
-    useSensor(KeyboardSensor, {
-      coordinateGetter: sortableKeyboardCoordinates,
-    }),
-  );
-
-  const panesById = useMemo(() => collectPanesById(layout.root), [layout.root]);
-  const explorerSidebarPane = useMemo(
-    () => findPaneById(layout.root, explorerSidebarPaneId),
-    [layout.root, explorerSidebarPaneId],
-  );
   const mainRoot = useMemo(
     () => removePaneFromSplitTree(layout.root, explorerSidebarPaneId),
     [layout.root, explorerSidebarPaneId],
@@ -408,434 +222,68 @@ export function SplitContainer({
       }),
     [focusModeEnabled, layout.focusedPaneId, mainRoot],
   );
-  const storedExplorerSidebarWidth = useWorkspaceLayoutStore(
-    (state) => state.explorerSidebarWidthByWorkspace[workspaceKey],
-  );
-  const resizeExplorerSidebar = useWorkspaceLayoutStore((state) => state.resizeExplorerSidebar);
-  const [workspaceShellWidth, setWorkspaceShellWidth] = useState(0);
-  const [previewExplorerSidebarWidth, setPreviewExplorerSidebarWidth] = useState<number | null>(
-    null,
-  );
-  const requestedExplorerSidebarWidth = previewExplorerSidebarWidth ?? storedExplorerSidebarWidth;
-  const explorerSidebarWidth = resolveExplorerSidebarWidth({
-    requestedWidth: requestedExplorerSidebarWidth,
-    containerWidth: workspaceShellWidth,
-  });
-  const explorerSidebarDockSizes = useMemo(
-    () =>
-      resolveExplorerSidebarDockSizes({
-        requestedWidth: requestedExplorerSidebarWidth,
-        containerWidth: workspaceShellWidth,
-      }),
-    [requestedExplorerSidebarWidth, workspaceShellWidth],
-  );
-  const renderExplorerSidebarDock = Boolean(
-    !focusModeEnabled && explorerSidebarPane && explorerSidebarPane.hidden !== true,
-  );
-  const mainColumnWindowChromeCorners = renderExplorerSidebarDock
-    ? removeWindowChromeCorner(inheritedWindowChromeCorners, "top-right")
-    : inheritedWindowChromeCorners;
+  const explorerPane = explorerSidebarPaneId
+    ? collectAllPanes(layout.root).find((pane) => pane.id === explorerSidebarPaneId)
+    : null;
+  const mainColumnWindowChromeCorners =
+    !focusModeEnabled && explorerPane && !explorerPane.hidden
+      ? removeWindowChromeCorner(inheritedWindowChromeCorners, "top-right")
+      : inheritedWindowChromeCorners;
   const mainColumnStyle = styles.mainColumn;
-  const explorerSidebarDockStyle = useMemo(
-    () => [styles.explorerSidebarDock, inlineUnistylesStyle({ width: explorerSidebarWidth })],
-    [explorerSidebarWidth],
-  );
-  const handleWorkspaceShellLayout = useCallback((event: LayoutChangeEvent) => {
-    const nextWidth = event.nativeEvent.layout.width;
-    setWorkspaceShellWidth((current) => (current === nextWidth ? current : nextWidth));
-  }, []);
-  const previewExplorerSidebarResize = useCallback(
-    (_groupId: string, sizes: number[]) => {
-      const nextRatio = sizes[1];
-      if (nextRatio !== undefined) {
-        setPreviewExplorerSidebarWidth(
-          resolveExplorerSidebarWidth({
-            requestedWidth: nextRatio * workspaceShellWidth,
-            containerWidth: workspaceShellWidth,
-          }),
-        );
-      }
-    },
-    [workspaceShellWidth],
-  );
-  const commitExplorerSidebarResize = useCallback(
-    (_groupId: string, sizes: number[]) => {
-      setPreviewExplorerSidebarWidth(null);
-      const nextRatio = sizes[1];
-      if (nextRatio !== undefined) {
-        resizeExplorerSidebar(
-          workspaceKey,
-          resolveExplorerSidebarWidth({
-            requestedWidth: nextRatio * workspaceShellWidth,
-            containerWidth: workspaceShellWidth,
-          }),
-        );
-      }
-    },
-    [resizeExplorerSidebar, workspaceKey, workspaceShellWidth],
-  );
   const renderRoot = useMemo(() => wrapRootPaneForStableMount(splitRoot.root), [splitRoot.root]);
-  const handleDragStart = useCallback((event: DragStartEvent) => {
-    const data = asWorkspaceTabDragData(event.active.data.current);
-    if (!data) {
-      setActiveDragTabId(null);
-      setDropPreview(null);
-      setTabDropPreview(null);
-      return;
-    }
-    setActiveDragTabId(data.tabId);
-  }, []);
-
-  const handleDragCancel = useCallback(() => {
-    setActiveDragTabId(null);
-    setDropPreview(null);
-    setTabDropPreview(null);
-  }, []);
-
-  const updateDropPreview = useCallback(
-    (event: Pick<DragMoveEvent, "active" | "over"> | Pick<DragOverEvent, "active" | "over">) => {
-      const activeData = asWorkspaceTabDragData(event.active.data.current);
-      const overData = asDragOverData(event.over?.data.current);
-
-      if (activeData?.kind !== "workspace-tab") {
-        setDropPreview(null);
-        setTabDropPreview(null);
-        return;
-      }
-
-      const rects = resolveDragMoveRects(event);
-      if (!rects) {
-        setDropPreview(null);
-        setTabDropPreview(null);
-        return;
-      }
-
-      const activeTab = uiTabs.find((tab) => tab.tabId === activeData.tabId) ?? null;
-      const destinationPaneId =
-        overData?.kind === "workspace-tab" || overData?.kind === "split-pane-drop"
-          ? overData.paneId
-          : null;
-      const destinationHost = destinationPaneId === explorerSidebarPaneId ? "explorer" : "main";
-      if (
-        !activeTab ||
-        !panelTargetSupportsHost(normalizedServerId, activeTab.target, destinationHost)
-      ) {
-        setDropPreview(null);
-        setTabDropPreview(null);
-        return;
-      }
-
-      if (overData?.kind === "workspace-tab") {
-        const preview = computeTabOverDropPreview({
-          activeData,
-          overData,
-          rects,
-          panesById,
-          uiTabs,
-        });
-        setDropPreview(null);
-        setTabDropPreview(preview);
-        return;
-      }
-
-      setTabDropPreview(null);
-      if (overData?.kind !== "split-pane-drop") {
-        setDropPreview(null);
-        return;
-      }
-
-      setDropPreview(computePaneOverDropPreview({ overData, rects }));
-    },
-    [normalizedServerId, panesById, explorerSidebarPaneId, uiTabs],
-  );
-
-  const applyTabDropEnd = useCallback(
-    (input: { activeData: WorkspaceTabDragData; overData: WorkspaceTabDragData }): void => {
-      const { activeData, overData } = input;
-      const sourcePane = panesById.get(activeData.paneId) ?? null;
-      const targetPane = panesById.get(overData.paneId) ?? null;
-      if (!sourcePane || !targetPane) {
-        return;
-      }
-
-      const sourceTabs = getWorkspacePaneDescriptors({ pane: sourcePane, tabs: uiTabs });
-      const targetTabs = getWorkspacePaneDescriptors({ pane: targetPane, tabs: uiTabs });
-      const sourceIndex = sourceTabs.findIndex((tab) => tab.tabId === activeData.tabId);
-      const resolvedTabDropPreview =
-        tabDropPreview?.paneId === overData.paneId ? tabDropPreview : null;
-      if (sourceIndex < 0 || !resolvedTabDropPreview) {
-        return;
-      }
-
-      if (activeData.paneId === overData.paneId) {
-        if (sourceIndex !== resolvedTabDropPreview.insertionIndex) {
-          const nextTabs = arrayMove(
-            sourceTabs,
-            sourceIndex,
-            resolvedTabDropPreview.insertionIndex,
-          );
-          onReorderTabsInPane(
-            activeData.paneId,
-            nextTabs.map((tab) => tab.tabId),
-          );
-        }
-        return;
-      }
-
-      const nextTargetTabIds = targetTabs.map((tab) => tab.tabId);
-      nextTargetTabIds.splice(resolvedTabDropPreview.insertionIndex, 0, activeData.tabId);
-      onMoveTabToPane(activeData.tabId, overData.paneId);
-      onReorderTabsInPane(overData.paneId, nextTargetTabIds);
-    },
-    [onMoveTabToPane, onReorderTabsInPane, panesById, tabDropPreview, uiTabs],
-  );
-
-  const applyPaneDropEnd = useCallback(
-    (input: { activeData: WorkspaceTabDragData; overData: SplitPaneDropData }): void => {
-      const { activeData, overData } = input;
-      if (dropPreview?.paneId !== overData.paneId) {
-        return;
-      }
-      if (dropPreview.position === "center") {
-        if (activeData.paneId !== overData.paneId) {
-          onMoveTabToPane(activeData.tabId, overData.paneId);
-        }
-        return;
-      }
-      onSplitPane({
-        tabId: activeData.tabId,
-        targetPaneId: overData.paneId,
-        position: dropPreview.position,
-      });
-    },
-    [dropPreview, onMoveTabToPane, onSplitPane],
-  );
-
-  const handleDragEnd = useCallback(
-    (event: DragEndEvent) => {
-      const activeData = asWorkspaceTabDragData(event.active.data.current);
-      const overData = asDragOverData(event.over?.data.current);
-
-      setActiveDragTabId(null);
-
-      if (activeData?.kind === "workspace-tab" && event.over) {
-        if (overData?.kind === "workspace-tab") {
-          applyTabDropEnd({ activeData, overData });
-        } else if (overData?.kind === "split-pane-drop") {
-          applyPaneDropEnd({ activeData, overData });
-        }
-      }
-
-      setDropPreview(null);
-      setTabDropPreview(null);
-    },
-    [applyTabDropEnd, applyPaneDropEnd],
-  );
-
   return (
     <RenderProfile id="SplitContainer">
-      <DndContext
-        sensors={sensors}
-        collisionDetection={dropCollisionDetection}
-        onDragStart={handleDragStart}
-        onDragMove={updateDropPreview}
-        onDragOver={updateDropPreview}
-        onDragCancel={handleDragCancel}
-        onDragEnd={handleDragEnd}
-      >
-        <View style={styles.workspaceShell} onLayout={handleWorkspaceShellLayout}>
-          <WindowChromeRegion corners={mainColumnWindowChromeCorners}>
-            <View style={mainColumnStyle}>
-              {renderMainHeader?.()}
-              {splitRoot.usesFallbackStrip && <WindowChromeSafeArea placement="below" />}
-              {renderRoot ? (
-                <SplitNodeView
-                  node={renderRoot}
-                  workspaceKey={workspaceKey}
-                  uiTabs={uiTabs}
-                  focusedPaneId={layout.focusedPaneId}
-                  normalizedServerId={normalizedServerId}
-                  normalizedWorkspaceId={normalizedWorkspaceId}
-                  isWorkspaceFocused={isWorkspaceFocused}
-                  hoveredCloseTabKey={hoveredCloseTabKey}
-                  setHoveredCloseTabKey={setHoveredCloseTabKey}
-                  closingTabIds={closingTabIds}
-                  onNavigateTab={onNavigateTab}
-                  onCloseTab={onCloseTab}
-                  onCopyResumeCommand={onCopyResumeCommand}
-                  onCopyAgentId={onCopyAgentId}
-                  onCopyTerminalId={onCopyTerminalId}
-                  onCopyFilePath={onCopyFilePath}
-                  onReloadAgent={onReloadAgent}
-                  onRenameTab={onRenameTab}
-                  onCloseTabsToLeft={onCloseTabsToLeft}
-                  onCloseTabsToRight={onCloseTabsToRight}
-                  onCloseOtherTabs={onCloseOtherTabs}
-                  onCreateNewTab={onCreateNewTab}
-                  buildPaneContentModel={buildPaneContentModel}
-                  onFocusPane={onFocusPane}
-                  onSplitPane={onSplitPane}
-                  onSplitPaneEmpty={onSplitPaneEmpty}
-                  onResizeSplit={onResizeSplit}
-                  onReorderTabsInPane={onReorderTabsInPane}
-                  activeDragTabId={activeDragTabId}
-                  showDropZones={activeDragTabId !== null}
-                  dropPreview={dropPreview}
-                  tabDropPreview={tabDropPreview}
-                  windowChromeCorners={splitRoot.usesFallbackStrip ? "none" : windowChromeCorners}
-                  maximizedPaneId={maximizedPaneId}
-                  workspaceHasMultiplePanes={workspaceHasMultiplePanes}
-                  onTogglePaneMaximized={handleTogglePaneMaximized}
-                  focusModeEnabled={focusModeEnabled}
-                  onExitFocusMode={onExitFocusMode}
-                />
-              ) : null}
-            </View>
-          </WindowChromeRegion>
-          {renderExplorerSidebarDock && explorerSidebarPane ? (
-            <>
-              <ResizeHandle
-                testID="workspace-explorer-sidebar-resize-handle"
-                direction="horizontal"
-                hitAreaAlignment="end"
-                groupId={EXPLORER_SIDEBAR_RESIZE_GROUP_ID}
-                index={0}
-                sizes={explorerSidebarDockSizes}
-                containerSize={workspaceShellWidth}
-                onPreviewResizeSplit={previewExplorerSidebarResize}
-                onResizeSplit={commitExplorerSidebarResize}
+      <View style={styles.workspaceShell}>
+        <WindowChromeRegion corners={mainColumnWindowChromeCorners}>
+          <View style={mainColumnStyle}>
+            {renderMainHeader?.()}
+            {splitRoot.usesFallbackStrip && <WindowChromeSafeArea placement="below" />}
+            {renderRoot ? (
+              <SplitNodeView
+                node={renderRoot}
+                workspaceKey={workspaceKey}
+                uiTabs={uiTabs}
+                focusedPaneId={layout.focusedPaneId}
+                normalizedServerId={normalizedServerId}
+                normalizedWorkspaceId={normalizedWorkspaceId}
+                isWorkspaceFocused={isWorkspaceFocused}
+                hoveredCloseTabKey={hoveredCloseTabKey}
+                setHoveredCloseTabKey={setHoveredCloseTabKey}
+                closingTabIds={closingTabIds}
+                onNavigateTab={onNavigateTab}
+                onCloseTab={onCloseTab}
+                onCopyResumeCommand={onCopyResumeCommand}
+                onCopyAgentId={onCopyAgentId}
+                onCopyTerminalId={onCopyTerminalId}
+                onCopyFilePath={onCopyFilePath}
+                onReloadAgent={onReloadAgent}
+                onRenameTab={onRenameTab}
+                onCloseTabsToLeft={onCloseTabsToLeft}
+                onCloseTabsToRight={onCloseTabsToRight}
+                onCloseOtherTabs={onCloseOtherTabs}
+                onCreateNewTab={onCreateNewTab}
+                buildPaneContentModel={buildPaneContentModel}
+                onFocusPane={onFocusPane}
+                onSplitPane={onSplitPane}
+                onSplitPaneEmpty={onSplitPaneEmpty}
+                onResizeSplit={onResizeSplit}
+                onReorderTabsInPane={onReorderTabsInPane}
+                activeDragTabId={activeDragTabId}
+                showDropZones={activeDragTabId !== null}
+                dropPreview={dropPreview}
+                tabDropPreview={tabDropPreview}
+                windowChromeCorners={splitRoot.usesFallbackStrip ? "none" : windowChromeCorners}
+                maximizedPaneId={maximizedPaneId}
+                workspaceHasMultiplePanes={workspaceHasMultiplePanes}
+                onTogglePaneMaximized={handleTogglePaneMaximized}
+                focusModeEnabled={focusModeEnabled}
+                onExitFocusMode={onExitFocusMode}
               />
-              <View style={explorerSidebarDockStyle}>
-                <ExplorerSidebarDock
-                  pane={explorerSidebarPane}
-                  uiTabs={uiTabs}
-                  normalizedServerId={normalizedServerId}
-                  normalizedWorkspaceId={normalizedWorkspaceId}
-                  isWorkspaceFocused={isWorkspaceFocused}
-                  closingTabIds={closingTabIds}
-                  onSelectTab={onSelectTabInPane}
-                  onCloseTab={onCloseTab}
-                  onCreateNewTab={onCreateNewTab}
-                  hoveredCloseTabKey={hoveredCloseTabKey}
-                  setHoveredCloseTabKey={setHoveredCloseTabKey}
-                  onCopyResumeCommand={onCopyResumeCommand}
-                  onCopyAgentId={onCopyAgentId}
-                  onCopyTerminalId={onCopyTerminalId}
-                  onCopyFilePath={onCopyFilePath}
-                  onReloadAgent={onReloadAgent}
-                  onRenameTab={onRenameTab}
-                  onCloseTabsToLeft={onCloseTabsToLeft}
-                  onCloseTabsToRight={onCloseTabsToRight}
-                  onCloseOtherTabs={onCloseOtherTabs}
-                  onExitFocusMode={onExitFocusMode}
-                  buildPaneContentModel={buildPaneContentModel}
-                  onReorderTabsInPane={onReorderTabsInPane}
-                  activeDragTabId={activeDragTabId}
-                  tabDropPreview={tabDropPreview}
-                  headerAction={renderExplorerSidebarHeaderAction?.()}
-                />
-              </View>
-            </>
-          ) : null}
-        </View>
-        <DragOverlay dropAnimation={null}>
-          {activeDragTabId ? (
-            <DragOverlayTabChip
-              tabId={activeDragTabId}
-              uiTabs={uiTabs}
-              normalizedServerId={normalizedServerId}
-              normalizedWorkspaceId={normalizedWorkspaceId}
-            />
-          ) : null}
-        </DragOverlay>
-      </DndContext>
-    </RenderProfile>
-  );
-}
-
-function DragOverlayTabChip({
-  tabId,
-  uiTabs,
-  normalizedServerId,
-  normalizedWorkspaceId,
-}: {
-  tabId: string;
-  uiTabs: WorkspaceTab[];
-  normalizedServerId: string;
-  normalizedWorkspaceId: string;
-}) {
-  const tab = uiTabs.find((t) => t.tabId === tabId);
-  const descriptor = useMemo<WorkspaceTabDescriptor | null>(
-    () =>
-      tab
-        ? {
-            key: tab.tabId,
-            tabId: tab.tabId,
-            kind: tab.target.kind,
-            target: tab.target,
-          }
-        : null,
-    [tab],
-  );
-  if (!descriptor) {
-    return null;
-  }
-  return (
-    <DragOverlayTabChipInner
-      tab={descriptor}
-      normalizedServerId={normalizedServerId}
-      normalizedWorkspaceId={normalizedWorkspaceId}
-    />
-  );
-}
-
-function DragOverlayTabChipInner({
-  tab,
-  normalizedServerId,
-  normalizedWorkspaceId,
-}: {
-  tab: WorkspaceTabDescriptor;
-  normalizedServerId: string;
-  normalizedWorkspaceId: string;
-}) {
-  const { t } = useTranslation();
-  const { theme } = useUnistyles();
-
-  const chipStyle = useMemo(
-    () => [
-      styles.dragOverlayChip,
-      {
-        backgroundColor: theme.colors.surface1,
-        borderColor: theme.colors.borderAccent,
-      },
-    ],
-    [theme.colors.surface1, theme.colors.borderAccent],
-  );
-  const chipLabelStyle = useMemo(
-    () => [styles.dragOverlayLabel, { color: theme.colors.foreground }],
-    [theme.colors.foreground],
-  );
-
-  return (
-    <WorkspaceTabPresentationResolver
-      tab={tab}
-      serverId={normalizedServerId}
-      workspaceId={normalizedWorkspaceId}
-    >
-      {(presentation) => {
-        const label =
-          presentation.titleState === "loading" ? t("common.states.loading") : presentation.label;
-
-        return (
-          <View style={chipStyle}>
-            <WorkspaceTabIcon presentation={presentation} active size={14} backdrop="surface1" />
-            <Text numberOfLines={1} style={chipLabelStyle}>
-              {label}
-            </Text>
+            ) : null}
           </View>
-        );
-      }}
-    </WorkspaceTabPresentationResolver>
+        </WindowChromeRegion>
+      </View>
+    </RenderProfile>
   );
 }
 
@@ -1317,21 +765,6 @@ const SplitPaneView = memo(function SplitPaneView({
   );
 });
 
-function collectPanesById(node: SplitNode): Map<string, SplitPane> {
-  const next = new Map<string, SplitPane>();
-  function visit(current: SplitNode) {
-    if (current.kind === "pane") {
-      next.set(current.pane.id, current.pane);
-      return;
-    }
-    for (const child of current.group.children) {
-      visit(child);
-    }
-  }
-  visit(node);
-  return next;
-}
-
 function getNodeKey(node: SplitNode): string {
   if (node.kind === "pane") {
     return node.pane.id;
@@ -1396,12 +829,6 @@ const styles = StyleSheet.create((theme) => ({
     minWidth: 0,
     minHeight: 0,
   },
-  explorerSidebarDock: {
-    flexShrink: 0,
-    minWidth: 240,
-    minHeight: 0,
-    backgroundColor: theme.colors.surfaceSidebar,
-  },
   group: {
     flex: 1,
     minWidth: 0,
@@ -1436,18 +863,4 @@ const styles = StyleSheet.create((theme) => ({
     minWidth: 0,
     minHeight: 0,
   },
-  dragOverlayChip: {
-    flexDirection: "row",
-    alignItems: "center",
-    gap: theme.spacing[2],
-    paddingHorizontal: theme.spacing[3],
-    paddingVertical: theme.spacing[1],
-    borderRadius: theme.borderRadius.md,
-    borderWidth: 1,
-    maxWidth: 200,
-  },
-  dragOverlayLabel: {
-    fontSize: theme.fontSize.base,
-    flexShrink: 1,
-  },
 }));

packages/app/src/components/split-drop-zone.tsx

@@ -147,7 +147,7 @@ function getPreviewFrameStyle(position: SplitDropZonePosition) {
 
 const styles = StyleSheet.create((theme) => ({
   overlay: {
-    ...StyleSheet.absoluteFillObject,
+    ...StyleSheet.absoluteFill,
     zIndex: 40,
   },
   previewOverlay: {

packages/app/src/components/terminal-pane.tsx

@@ -1171,7 +1171,7 @@ const styles = StyleSheet.create((theme) => ({
     minHeight: 0,
   },
   attachOverlay: {
-    ...StyleSheet.absoluteFillObject,
+    ...StyleSheet.absoluteFill,
     alignItems: "center",
     justifyContent: "center",
     backgroundColor: "rgba(0, 0, 0, 0.16)",

packages/app/src/components/ui/combobox.tsx

@@ -1765,7 +1765,7 @@ const styles = StyleSheet.create((theme) => ({
     flex: 1,
   },
   desktopOverlayWeb: {
-    ...StyleSheet.absoluteFillObject,
+    ...StyleSheet.absoluteFill,
     pointerEvents: "auto" as const,
   },
   desktopBackdrop: {

packages/app/src/components/ui/floating-panel-portal.tsx

@@ -81,6 +81,6 @@ export function FloatingPanelPortalHost({
 
 const styles = StyleSheet.create({
   host: {
-    ...StyleSheet.absoluteFillObject,
+    ...StyleSheet.absoluteFill,
   },
 });

packages/app/src/components/ui/hover-card.tsx

@@ -14,13 +14,16 @@ import { Dimensions, View, type Role, type StyleProp, type ViewStyle } from "rea
 import { FadeIn, FadeOut } from "react-native-reanimated";
 import { StyleSheet } from "react-native-unistyles";
 import { Portal } from "@gorhom/portal";
-import { useBottomSheetModalInternal } from "@gorhom/bottom-sheet";
 import {
   OverlayLayerProvider,
   useOverlayLayer,
   useWebOverlayRegistration,
 } from "@/lib/overlay-root";
 import { FloatingSurface } from "@/components/ui/floating";
+import {
+  measureFloatingPanelPortalHost,
+  useFloatingPanelPortalHostName,
+} from "@/components/ui/floating-panel-portal";
 import { isWeb } from "@/constants/platform";
 import { useHoverSafeZone } from "@/hooks/use-hover-safe-zone";
 import {
@@ -326,28 +329,31 @@ function HoverCardSurface({
   triggerRef: RefObject<View | null>;
   contentRef: RefObject<View | null>;
 }): ReactElement {
-  const bottomSheetInternal = useBottomSheetModalInternal(true);
-  const [triggerRect, setTriggerRect] = useState<Rect | null>(null);
+  const portalHostName = useFloatingPanelPortalHostName();
+  const [anchor, setAnchor] = useState<{ triggerRect: Rect; hostRect: Rect } | null>(null);
   const [contentSize, setContentSize] = useState<Size | null>(null);
   const [position, setPosition] = useState<{ x: number; y: number } | null>(null);
 
   useEffect(() => {
     if (!triggerRef.current) return;
     let cancelled = false;
-    void measureElement(triggerRef.current).then((rect) => {
-      if (!cancelled) setTriggerRect(rect);
+    void Promise.all([
+      measureElement(triggerRef.current),
+      measureFloatingPanelPortalHost(portalHostName),
+    ]).then(([triggerRect, hostRect]) => {
+      if (!cancelled && hostRect) setAnchor({ triggerRect, hostRect });
       return undefined;
     });
     return () => {
       cancelled = true;
     };
-  }, [triggerRef]);
+  }, [portalHostName, triggerRef]);
 
   useEffect(() => {
-    if (!triggerRect || !contentSize) return;
+    if (!anchor || !contentSize) return;
     const { width, height } = Dimensions.get("window");
     const { x, y } = computePosition({
-      triggerRect,
+      triggerRect: anchor.triggerRect,
       contentSize,
       displayArea: { x: 0, y: 0, width, height },
       placement,
@@ -355,8 +361,8 @@ function HoverCardSurface({
       alignment,
       offset,
     });
-    setPosition({ x, y });
-  }, [alignment, contentSize, offset, placement, triggerRect]);
+    setPosition({ x: x - anchor.hostRect.x, y: y - anchor.hostRect.y });
+  }, [alignment, anchor, contentSize, offset, placement]);
 
   const handleLayout = useCallback(
     (event: { nativeEvent: { layout: { width: number; height: number } } }) => {
@@ -377,7 +383,7 @@ function HoverCardSurface({
   const surfaceStyle = useMemo(() => [styles.surface, style], [style]);
 
   return (
-    <Portal hostName={bottomSheetInternal?.hostName}>
+    <Portal hostName={portalHostName}>
       <View pointerEvents="box-none" style={[styles.portalOverlay, { zIndex: layer }]}>
         <FloatingSurface
           ref={contentRef}

packages/app/src/components/ui/isolated-bottom-sheet-modal/host-scope.tsx

@@ -86,6 +86,6 @@ const styles = StyleSheet.create({
     minHeight: 0,
   },
   host: {
-    ...StyleSheet.absoluteFillObject,
+    ...StyleSheet.absoluteFill,
   },
 });

packages/app/src/components/ui/menu/menu-overlay.tsx

@@ -527,7 +527,7 @@ const styles = StyleSheet.create((theme) => ({
     flex: 1,
   },
   overlayWeb: {
-    ...StyleSheet.absoluteFillObject,
+    ...StyleSheet.absoluteFill,
     pointerEvents: "auto" as const,
   },
   backdrop: {

packages/app/src/components/ui/press-highlight.native.tsx

@@ -66,9 +66,9 @@ export const PressHighlight = forwardRef<View, PressHighlightProps>(function Pre
 
 const styles = StyleSheet.create({
   highlight: {
-    ...StyleSheet.absoluteFillObject,
+    ...StyleSheet.absoluteFill,
   },
   highlightFill: {
-    ...StyleSheet.absoluteFillObject,
+    ...StyleSheet.absoluteFill,
   },
 });

packages/app/src/components/ui/shortcut.tsx

@@ -68,7 +68,7 @@ const styles = StyleSheet.create((theme) => ({
     borderWidth: 0,
   },
   badgeBackground: {
-    ...StyleSheet.absoluteFillObject,
+    ...StyleSheet.absoluteFill,
     borderRadius: theme.borderRadius.md,
     backgroundColor: theme.colors.surface3,
     opacity: theme.opacity[50],

packages/app/src/components/workspace-tab-drag-context.ts

@@ -0,0 +1,12 @@
+import { createContext, useContext } from "react";
+import type { TabDropPreview } from "./split-container-tab-drop-preview";
+import type { SplitDropZoneHover } from "./split-drop-zone";
+export const WorkspaceTabDragContext = createContext<{
+  activeDragTabId: string | null;
+  dropPreview: SplitDropZoneHover | null;
+  tabDropPreview: TabDropPreview | null;
+  externalDndContext: boolean;
+}>({ activeDragTabId: null, dropPreview: null, tabDropPreview: null, externalDndContext: false });
+export function useWorkspaceTabDrag() {
+  return useContext(WorkspaceTabDragContext);
+}

packages/app/src/components/workspace-tab-drag-policy.ts

@@ -0,0 +1,9 @@
+export function acceptsWorkspaceTabDrop(
+  allowCrossPane: boolean,
+  sourcePaneId: string,
+  destination: { kind: "workspace-tab" | "split-pane-drop"; paneId: string },
+): boolean {
+  return (
+    allowCrossPane || (destination.kind === "workspace-tab" && sourcePaneId === destination.paneId)
+  );
+}

packages/app/src/components/workspace-tab-drag-scope.tsx

@@ -0,0 +1,5 @@
+import type { ComponentProps } from "react";
+import type { WorkspaceTabDragScope as WebScope } from "./workspace-tab-drag-scope.web";
+export function WorkspaceTabDragScope({ children }: ComponentProps<typeof WebScope>) {
+  return children;
+}

packages/app/src/components/workspace-tab-drag-scope.web.tsx

@@ -0,0 +1,494 @@
+import { useCallback, useMemo, useState, type ReactNode } from "react";
+import { View, Text } from "react-native";
+import { useTranslation } from "react-i18next";
+import { StyleSheet } from "react-native-unistyles";
+import {
+  DndContext,
+  DragOverlay,
+  KeyboardSensor,
+  PointerSensor,
+  closestCenter,
+  pointerWithin,
+  useSensor,
+  useSensors,
+  type CollisionDetection,
+  type DragEndEvent,
+  type DragMoveEvent,
+  type DragOverEvent,
+  type DragStartEvent,
+} from "@dnd-kit/core";
+import { arrayMove, sortableKeyboardCoordinates } from "@dnd-kit/sortable";
+import { computeTabDropPreview, type TabDropPreview } from "./split-container-tab-drop-preview";
+import { resolveSplitDropPosition, type SplitDropZoneHover } from "./split-drop-zone";
+import { getWorkspacePaneDescriptors } from "@/screens/workspace/workspace-pane-state";
+import {
+  WorkspaceTabPresentationResolver,
+  WorkspaceTabIcon,
+} from "@/screens/workspace/workspace-tab-presentation";
+import type { WorkspaceTabDescriptor } from "@/screens/workspace/workspace-tabs-types";
+import {
+  collectAllPanes,
+  createWorkspaceLayoutWithExplorerSidebar,
+  type WorkspaceLayout,
+  type SplitPane,
+} from "@/stores/workspace-layout-store";
+import type { WorkspaceTab } from "@/workspace-tabs/model";
+import { panelTargetSupportsHost } from "@/plugins/workspace-panels/locations";
+import { acceptsWorkspaceTabDrop } from "./workspace-tab-drag-policy";
+import { WorkspaceTabDragContext } from "./workspace-tab-drag-context";
+interface WorkspaceTabDragData {
+  kind: "workspace-tab";
+  paneId: string;
+  tabId: string;
+}
+
+interface SplitPaneDropData {
+  kind: "split-pane-drop";
+  paneId: string;
+}
+
+function isWorkspaceTabDragData(data: unknown): data is WorkspaceTabDragData {
+  return typeof data === "object" && data !== null && Reflect.get(data, "kind") === "workspace-tab";
+}
+
+function isSplitPaneDropData(data: unknown): data is SplitPaneDropData {
+  return (
+    typeof data === "object" && data !== null && Reflect.get(data, "kind") === "split-pane-drop"
+  );
+}
+
+function asWorkspaceTabDragData(data: unknown): WorkspaceTabDragData | undefined {
+  return isWorkspaceTabDragData(data) ? data : undefined;
+}
+
+function asDragOverData(data: unknown): WorkspaceTabDragData | SplitPaneDropData | undefined {
+  if (isWorkspaceTabDragData(data)) return data;
+  if (isSplitPaneDropData(data)) return data;
+  return undefined;
+}
+
+interface DragMoveRects {
+  translatedRect: { left: number; top: number; width: number; height: number };
+  overRect: { left: number; top: number; width: number; height: number };
+}
+
+function resolveDragMoveRects(
+  event: Pick<DragMoveEvent, "active" | "over"> | Pick<DragOverEvent, "active" | "over">,
+): DragMoveRects | null {
+  const translatedRect = event.active.rect.current.translated;
+  const overRect = event.over?.rect;
+  if (!translatedRect || !overRect || overRect.width <= 0 || overRect.height <= 0) {
+    return null;
+  }
+  return { translatedRect, overRect };
+}
+
+function computeTabOverDropPreview(input: {
+  activeData: WorkspaceTabDragData;
+  overData: WorkspaceTabDragData;
+  rects: DragMoveRects;
+  panesById: Map<string, SplitPane>;
+  uiTabs: WorkspaceTab[];
+}): TabDropPreview | null {
+  const { activeData, overData, rects, panesById, uiTabs } = input;
+  const targetPane = panesById.get(overData.paneId) ?? null;
+  if (!targetPane) {
+    return null;
+  }
+  const targetTabs = getWorkspacePaneDescriptors({ pane: targetPane, tabs: uiTabs });
+  return computeTabDropPreview({
+    activePaneId: activeData.paneId,
+    activeTabId: activeData.tabId,
+    overPaneId: overData.paneId,
+    overTabId: overData.tabId,
+    targetTabs,
+    activeRect: {
+      left: rects.translatedRect.left,
+      width: rects.translatedRect.width,
+    },
+    overRect: {
+      left: rects.overRect.left,
+      width: rects.overRect.width,
+    },
+  });
+}
+
+function computePaneOverDropPreview(input: {
+  overData: SplitPaneDropData;
+  rects: DragMoveRects;
+}): SplitDropZoneHover | null {
+  const { overData, rects } = input;
+  const centerX = rects.translatedRect.left + rects.translatedRect.width / 2;
+  const centerY = rects.translatedRect.top + rects.translatedRect.height / 2;
+  const relativeX = centerX - rects.overRect.left;
+  const relativeY = centerY - rects.overRect.top;
+  if (
+    Number.isNaN(relativeX) ||
+    Number.isNaN(relativeY) ||
+    relativeX < 0 ||
+    relativeX > rects.overRect.width ||
+    relativeY < 0 ||
+    relativeY > rects.overRect.height
+  ) {
+    return null;
+  }
+  return {
+    paneId: overData.paneId,
+    position: resolveSplitDropPosition({
+      width: rects.overRect.width,
+      height: rects.overRect.height,
+      x: relativeX,
+      y: relativeY,
+    }),
+  };
+}
+
+const dropCollisionDetection: CollisionDetection = (args) => {
+  const pointerHits = pointerWithin(args);
+  const tabHits = pointerHits.filter(
+    (entry) => entry.data?.droppableContainer.data.current?.kind === "workspace-tab",
+  );
+  if (tabHits.length > 0) {
+    return tabHits;
+  }
+
+  const paneHits = pointerHits.filter(
+    (entry) => entry.data?.droppableContainer.data.current?.kind === "split-pane-drop",
+  );
+  if (paneHits.length > 0) {
+    return paneHits;
+  }
+
+  return closestCenter(args);
+};
+
+const EMPTY_LAYOUT = createWorkspaceLayoutWithExplorerSidebar();
+
+interface WorkspaceTabDragScopeProps {
+  children: ReactNode;
+  layout: WorkspaceLayout | null;
+  explorerSidebarPaneId: string | null;
+  allowCrossPane: boolean;
+  normalizedServerId: string;
+  normalizedWorkspaceId: string;
+  uiTabs: WorkspaceTab[];
+  onMoveTabToPane: (tabId: string, paneId: string) => void;
+  onReorderTabsInPane: (paneId: string, tabIds: string[]) => void;
+  onSplitPane: (input: {
+    tabId: string;
+    targetPaneId: string;
+    position: "left" | "right" | "top" | "bottom";
+  }) => void;
+}
+export function WorkspaceTabDragScope({
+  children,
+  layout,
+  explorerSidebarPaneId,
+  allowCrossPane,
+  normalizedServerId,
+  normalizedWorkspaceId,
+  uiTabs,
+  onMoveTabToPane,
+  onReorderTabsInPane,
+  onSplitPane,
+}: WorkspaceTabDragScopeProps) {
+  const [activeDragTabId, setActiveDragTabId] = useState<string | null>(null);
+  const [dropPreview, setDropPreview] = useState<SplitDropZoneHover | null>(null);
+  const [tabDropPreview, setTabDropPreview] = useState<TabDropPreview | null>(null);
+  const sensors = useSensors(
+    useSensor(PointerSensor, {
+      activationConstraint: {
+        distance: 8,
+      },
+    }),
+    useSensor(KeyboardSensor, {
+      coordinateGetter: sortableKeyboardCoordinates,
+    }),
+  );
+
+  const panesById = useMemo(
+    () => new Map(collectAllPanes((layout ?? EMPTY_LAYOUT).root).map((pane) => [pane.id, pane])),
+    [layout],
+  );
+  const handleDragStart = useCallback((event: DragStartEvent) => {
+    const data = asWorkspaceTabDragData(event.active.data.current);
+    if (!data) {
+      setActiveDragTabId(null);
+      setDropPreview(null);
+      setTabDropPreview(null);
+      return;
+    }
+    setActiveDragTabId(data.tabId);
+  }, []);
+
+  const handleDragCancel = useCallback(() => {
+    setActiveDragTabId(null);
+    setDropPreview(null);
+    setTabDropPreview(null);
+  }, []);
+
+  const updateDropPreview = useCallback(
+    (event: Pick<DragMoveEvent, "active" | "over"> | Pick<DragOverEvent, "active" | "over">) => {
+      const activeData = asWorkspaceTabDragData(event.active.data.current);
+      const overData = asDragOverData(event.over?.data.current);
+
+      if (
+        !activeData ||
+        !overData ||
+        !acceptsWorkspaceTabDrop(allowCrossPane, activeData.paneId, overData)
+      ) {
+        setDropPreview(null);
+        setTabDropPreview(null);
+        return;
+      }
+
+      const rects = resolveDragMoveRects(event);
+      if (!rects) {
+        setDropPreview(null);
+        setTabDropPreview(null);
+        return;
+      }
+
+      const activeTab = uiTabs.find((tab) => tab.tabId === activeData.tabId) ?? null;
+      const destinationPaneId =
+        overData?.kind === "workspace-tab" || overData?.kind === "split-pane-drop"
+          ? overData.paneId
+          : null;
+      const destinationHost = destinationPaneId === explorerSidebarPaneId ? "explorer" : "main";
+      if (
+        !activeTab ||
+        !panelTargetSupportsHost(normalizedServerId, activeTab.target, destinationHost)
+      ) {
+        setDropPreview(null);
+        setTabDropPreview(null);
+        return;
+      }
+
+      if (overData?.kind === "workspace-tab") {
+        const preview = computeTabOverDropPreview({
+          activeData,
+          overData,
+          rects,
+          panesById,
+          uiTabs,
+        });
+        setDropPreview(null);
+        setTabDropPreview(preview);
+        return;
+      }
+
+      setTabDropPreview(null);
+      if (overData?.kind !== "split-pane-drop") {
+        setDropPreview(null);
+        return;
+      }
+
+      setDropPreview(computePaneOverDropPreview({ overData, rects }));
+    },
+    [allowCrossPane, normalizedServerId, panesById, explorerSidebarPaneId, uiTabs],
+  );
+
+  const applyTabDropEnd = useCallback(
+    (input: { activeData: WorkspaceTabDragData; overData: WorkspaceTabDragData }): void => {
+      const { activeData, overData } = input;
+      const sourcePane = panesById.get(activeData.paneId) ?? null;
+      const targetPane = panesById.get(overData.paneId) ?? null;
+      if (!sourcePane || !targetPane) {
+        return;
+      }
+
+      const sourceTabs = getWorkspacePaneDescriptors({ pane: sourcePane, tabs: uiTabs });
+      const targetTabs = getWorkspacePaneDescriptors({ pane: targetPane, tabs: uiTabs });
+      const sourceIndex = sourceTabs.findIndex((tab) => tab.tabId === activeData.tabId);
+      const resolvedTabDropPreview =
+        tabDropPreview?.paneId === overData.paneId ? tabDropPreview : null;
+      if (sourceIndex < 0 || !resolvedTabDropPreview) {
+        return;
+      }
+
+      if (activeData.paneId === overData.paneId) {
+        if (sourceIndex !== resolvedTabDropPreview.insertionIndex) {
+          const nextTabs = arrayMove(
+            sourceTabs,
+            sourceIndex,
+            resolvedTabDropPreview.insertionIndex,
+          );
+          onReorderTabsInPane(
+            activeData.paneId,
+            nextTabs.map((tab) => tab.tabId),
+          );
+        }
+        return;
+      }
+
+      const nextTargetTabIds = targetTabs.map((tab) => tab.tabId);
+      nextTargetTabIds.splice(resolvedTabDropPreview.insertionIndex, 0, activeData.tabId);
+      onMoveTabToPane(activeData.tabId, overData.paneId);
+      onReorderTabsInPane(overData.paneId, nextTargetTabIds);
+    },
+    [onMoveTabToPane, onReorderTabsInPane, panesById, tabDropPreview, uiTabs],
+  );
+
+  const applyPaneDropEnd = useCallback(
+    (input: { activeData: WorkspaceTabDragData; overData: SplitPaneDropData }): void => {
+      const { activeData, overData } = input;
+      if (dropPreview?.paneId !== overData.paneId) {
+        return;
+      }
+      if (dropPreview.position === "center") {
+        if (activeData.paneId !== overData.paneId) {
+          onMoveTabToPane(activeData.tabId, overData.paneId);
+        }
+        return;
+      }
+      onSplitPane({
+        tabId: activeData.tabId,
+        targetPaneId: overData.paneId,
+        position: dropPreview.position,
+      });
+    },
+    [dropPreview, onMoveTabToPane, onSplitPane],
+  );
+
+  const handleDragEnd = useCallback(
+    (event: DragEndEvent) => {
+      const activeData = asWorkspaceTabDragData(event.active.data.current);
+      const overData = asDragOverData(event.over?.data.current);
+
+      setActiveDragTabId(null);
+
+      if (
+        activeData &&
+        overData &&
+        event.over &&
+        acceptsWorkspaceTabDrop(allowCrossPane, activeData.paneId, overData)
+      ) {
+        if (overData?.kind === "workspace-tab") {
+          applyTabDropEnd({ activeData, overData });
+        } else if (overData?.kind === "split-pane-drop") {
+          applyPaneDropEnd({ activeData, overData });
+        }
+      }
+
+      setDropPreview(null);
+      setTabDropPreview(null);
+    },
+    [allowCrossPane, applyTabDropEnd, applyPaneDropEnd],
+  );
+
+  const context = useMemo(
+    () => ({ activeDragTabId, dropPreview, tabDropPreview, externalDndContext: true }),
+    [activeDragTabId, dropPreview, tabDropPreview],
+  );
+  return (
+    <DndContext
+      sensors={sensors}
+      collisionDetection={dropCollisionDetection}
+      onDragStart={handleDragStart}
+      onDragMove={updateDropPreview}
+      onDragOver={updateDropPreview}
+      onDragCancel={handleDragCancel}
+      onDragEnd={handleDragEnd}
+    >
+      <WorkspaceTabDragContext value={context}>{children}</WorkspaceTabDragContext>
+      <DragOverlay dropAnimation={null}>
+        {activeDragTabId ? (
+          <DragOverlayTabChip
+            tabId={activeDragTabId}
+            uiTabs={uiTabs}
+            normalizedServerId={normalizedServerId}
+            normalizedWorkspaceId={normalizedWorkspaceId}
+          />
+        ) : null}
+      </DragOverlay>
+    </DndContext>
+  );
+}
+function DragOverlayTabChip({
+  tabId,
+  uiTabs,
+  normalizedServerId,
+  normalizedWorkspaceId,
+}: {
+  tabId: string;
+  uiTabs: WorkspaceTab[];
+  normalizedServerId: string;
+  normalizedWorkspaceId: string;
+}) {
+  const tab = uiTabs.find((t) => t.tabId === tabId);
+  const descriptor = useMemo<WorkspaceTabDescriptor | null>(
+    () =>
+      tab
+        ? {
+            key: tab.tabId,
+            tabId: tab.tabId,
+            kind: tab.target.kind,
+            target: tab.target,
+          }
+        : null,
+    [tab],
+  );
+  if (!descriptor) {
+    return null;
+  }
+  return (
+    <DragOverlayTabChipInner
+      tab={descriptor}
+      normalizedServerId={normalizedServerId}
+      normalizedWorkspaceId={normalizedWorkspaceId}
+    />
+  );
+}
+
+function DragOverlayTabChipInner({
+  tab,
+  normalizedServerId,
+  normalizedWorkspaceId,
+}: {
+  tab: WorkspaceTabDescriptor;
+  normalizedServerId: string;
+  normalizedWorkspaceId: string;
+}) {
+  const { t } = useTranslation();
+  return (
+    <WorkspaceTabPresentationResolver
+      tab={tab}
+      serverId={normalizedServerId}
+      workspaceId={normalizedWorkspaceId}
+    >
+      {(presentation) => {
+        const label =
+          presentation.titleState === "loading" ? t("common.states.loading") : presentation.label;
+
+        return (
+          <View style={styles.dragOverlayChip}>
+            <WorkspaceTabIcon presentation={presentation} active size={14} backdrop="surface1" />
+            <Text numberOfLines={1} style={styles.dragOverlayLabel}>
+              {label}
+            </Text>
+          </View>
+        );
+      }}
+    </WorkspaceTabPresentationResolver>
+  );
+}
+
+const styles = StyleSheet.create((theme) => ({
+  dragOverlayChip: {
+    backgroundColor: theme.colors.surface1,
+    borderColor: theme.colors.borderAccent,
+    flexDirection: "row",
+    alignItems: "center",
+    gap: theme.spacing[2],
+    paddingHorizontal: theme.spacing[3],
+    paddingVertical: theme.spacing[1],
+    borderRadius: theme.borderRadius.md,
+    borderWidth: 1,
+    maxWidth: 200,
+  },
+  dragOverlayLabel: {
+    color: theme.colors.foreground,
+    fontSize: theme.fontSize.base,
+    flexShrink: 1,
+  },
+}));

packages/app/src/composer/draft/workspace-tab.tsx

@@ -415,11 +415,10 @@ export function WorkspaceDraftAgentTab({
       openWorkspaceChanges({
         isCompact: isCompactFormFactor,
         workspaceKey: buildWorkspaceTabPersistenceKey({ serverId, workspaceId: workspaceId ?? "" }),
-        checkout: { serverId, cwd: composerState.workingDir, isGit: true },
         preferences: openInSidePane,
       });
     },
-    [composerState.workingDir, isCompactFormFactor, openInSidePane, serverId, workspaceId],
+    [isCompactFormFactor, openInSidePane, serverId, workspaceId],
   );
 
   const {

packages/app/src/constants/layout.ts

@@ -33,7 +33,7 @@ export {
   getIsElectronMac as getIsElectronRuntimeMac,
 } from "./platform";
 
-/** Compact layouts are the breakpoints below `md`. */
+/** Below 600 points, sidebars overlay the workspace. Medium and wider layouts dock them. */
 export function isCompactBreakpoint(breakpoint: string | undefined): boolean {
   return breakpoint === "xs" || breakpoint === "sm";
 }

packages/app/src/contexts/session-context.tsx

@@ -56,10 +56,7 @@ export type { DraftInput } from "@/stores/draft-store";
 export type {
   Agent,
   ExplorerEntry,
-  ExplorerFile,
   ExplorerEntryKind,
-  ExplorerFileKind,
-  ExplorerEncoding,
   AgentFileExplorerState,
 } from "@/stores/session-store";
 

packages/app/src/desktop/components/integrations-section.tsx

@@ -1,7 +1,7 @@
 import { useCallback, useMemo } from "react";
 import { useTranslation } from "react-i18next";
 import { Text, View } from "react-native";
-import { useFocusEffect } from "@react-navigation/native";
+import { useFocusEffect } from "expo-router/react-navigation";
 import { StyleSheet, useUnistyles } from "react-native-unistyles";
 import { ArrowUpRight, Check, Terminal } from "lucide-react-native";
 import { Button } from "@/components/ui/button";

packages/app/src/file-explorer/read-result.test.ts

@@ -1,34 +0,0 @@
-import type { FileReadResult } from "@getpaseo/client/internal/daemon-client";
-import { describe, expect, it } from "vitest";
-import { explorerFileFromReadResult } from "./read-result";
-
-function textRead(bytes: Uint8Array): FileReadResult {
-  return {
-    bytes,
-    mime: "text/plain",
-    size: bytes.byteLength,
-    path: "notes.txt",
-    kind: "text",
-    modifiedAt: "2026-07-21T00:00:00.000Z",
-  };
-}
-
-describe("explorerFileFromReadResult", () => {
-  it("records and hides a leading UTF-8 BOM", () => {
-    const file = explorerFileFromReadResult(
-      textRead(new Uint8Array([0xef, 0xbb, 0xbf, 0x68, 0x69])),
-    );
-
-    expect(file).toMatchObject({ content: "hi", hasBom: true });
-  });
-
-  it("does not mark BOM-free text or non-leading U+FEFF as BOM files", () => {
-    const plain = explorerFileFromReadResult(textRead(new TextEncoder().encode("hi")));
-    const embedded = explorerFileFromReadResult(
-      textRead(new Uint8Array([0x68, 0x69, 0xef, 0xbb, 0xbf])),
-    );
-
-    expect(plain.hasBom).toBe(false);
-    expect(embedded.hasBom).toBe(false);
-  });
-});

packages/app/src/file-explorer/read-result.ts

@@ -1,21 +0,0 @@
-import type { FileReadResult } from "@getpaseo/client/internal/daemon-client";
-import type { ExplorerFile } from "@/stores/session-store";
-
-export function explorerFileFromReadResult(file: FileReadResult): ExplorerFile {
-  const isText = file.kind === "text";
-  return {
-    path: file.path,
-    kind: file.kind,
-    encoding: isText ? "utf-8" : "none",
-    content: isText ? new TextDecoder().decode(file.bytes) : undefined,
-    hasBom: isText && hasUtf8Bom(file.bytes),
-    mimeType: file.mime,
-    size: file.size,
-    modifiedAt: file.modifiedAt,
-    revision: file.revision,
-  };
-}
-
-function hasUtf8Bom(bytes: Uint8Array): boolean {
-  return bytes.length >= 3 && bytes[0] === 0xef && bytes[1] === 0xbb && bytes[2] === 0xbf;
-}

packages/app/src/file-pane/bar.tsx

@@ -1,126 +1,42 @@
-import { Text, View } from "react-native";
-import { StyleSheet, withUnistyles } from "react-native-unistyles";
+import { View } from "react-native";
+import { StyleSheet } from "react-native-unistyles";
 import { useTranslation } from "react-i18next";
-import { LoadingSpinner } from "@/components/ui/loading-spinner";
 import { PaneContentToolbar } from "@/components/ui/pane-content-toolbar";
-import { SegmentedControl } from "@/components/ui/segmented-control";
-import type { Theme } from "@/styles/theme";
-import { FileConflictAlert, type FileConflictAlertState } from "./conflict-alert";
-import type { FileEditorStatus } from "./editor/model";
+import {
+  FilePanelBarMenu,
+  FilePanelSwitcher,
+  useFilePanelChoiceSnapshot,
+  type FilePanelChoice,
+} from "@/file-panels";
 
-const ThemedSpinner = withUnistyles(LoadingSpinner);
-const spinnerMapping = (theme: Theme) => ({ color: theme.colors.foregroundMuted });
-
-export function FilePanelBar({
-  size,
-  lineCount,
-  mode,
-  onModeChange,
-  editorStatus,
-  cursor,
-  vimMode,
-  conflict,
-}: {
-  size: number;
-  lineCount?: number;
-  mode?: "preview" | "source";
-  onModeChange?(mode: "preview" | "source"): void;
-  editorStatus?: FileEditorStatus;
-  cursor?: { line: number; column: number };
-  vimMode?: string | null;
-  conflict?: FileConflictAlertState;
-}) {
+/**
+ * The file tab's bar: the switcher between the file's panels, "Open with…", and whether the panel
+ * has unsaved changes. Shown only when the file has more than one panel; the panel shows the rest.
+ */
+export function FilePanelBar({ choice, modified }: { choice: FilePanelChoice; modified: boolean }) {
   const { t } = useTranslation();
-  const previewModes = [
-    {
-      value: "preview" as const,
-      label: t("panels.file.editor.preview"),
-      testID: "file-mode-preview",
-    },
-    { value: "source" as const, label: t("panels.file.editor.source"), testID: "file-mode-source" },
-  ];
+  const { openWith } = useFilePanelChoiceSnapshot(choice);
+  if (!openWith) return null;
   return (
     <View style={styles.chrome}>
       <PaneContentToolbar testID="file-panel-bar">
         <View style={styles.row}>
-          <View style={styles.metadata}>
-            <Text
-              style={styles.whisper}
-              accessibilityLabel={t("panels.file.editor.fileSize", { size: formatFileSize(size) })}
-            >
-              {formatFileSize(size)}
-            </Text>
-            {lineCount !== undefined ? (
-              <Text
-                style={styles.whisper}
-                accessibilityLabel={t("panels.file.editor.lines", { count: lineCount })}
-              >
-                {t("panels.file.editor.lines", { count: lineCount })}
-              </Text>
-            ) : null}
-          </View>
-          <View
-            style={styles.status}
-            accessibilityLabel={
-              editorStatus
-                ? t("panels.file.editor.editorStatus", { status: editorStatus })
-                : undefined
-            }
-          >
-            {editorStatus === "dirty" ? (
-              <View
-                style={styles.dirtyDot}
-                accessibilityLabel={t("panels.file.editor.unsavedChanges")}
-              />
-            ) : null}
-            {editorStatus === "saving" ? (
-              <>
-                <ThemedSpinner size={14} uniProps={spinnerMapping} />
-                <Text style={styles.secondary}>{t("panels.file.editor.saving")}</Text>
-              </>
-            ) : null}
-            {editorStatus === "error" ? (
-              <Text style={styles.error}>{t("panels.file.editor.saveFailed")}</Text>
-            ) : null}
-            {vimMode ? (
-              <Text
-                style={styles.vim}
-                accessibilityLabel={t("panels.file.editor.vimMode", { mode: vimMode })}
-              >
-                {vimMode}
-              </Text>
-            ) : null}
-            {cursor ? (
-              <Text
-                style={styles.whisper}
-                accessibilityLabel={t("panels.file.editor.cursor", cursor)}
-              >
-                Ln {cursor.line}, Col {cursor.column}
-              </Text>
-            ) : null}
-          </View>
-          {mode && onModeChange ? (
-            <SegmentedControl
-              size="xs"
-              value={mode}
-              onValueChange={onModeChange}
-              testID="file-preview-mode"
-              options={previewModes}
+          <View style={styles.spacer} />
+          {modified ? (
+            <View
+              style={styles.modifiedDot}
+              accessibilityLabel={t("panels.file.editor.unsavedChanges")}
+              testID="file-panel-modified"
             />
           ) : null}
+          <FilePanelSwitcher choice={choice} />
+          <FilePanelBarMenu choice={choice} />
         </View>
       </PaneContentToolbar>
-      {conflict ? <FileConflictAlert state={conflict} /> : null}
     </View>
   );
 }
 
-function formatFileSize(size: number): string {
-  if (size < 1024) return `${size} B`;
-  if (size < 1024 * 1024) return `${(size / 1024).toFixed(1)} KB`;
-  return `${(size / (1024 * 1024)).toFixed(1)} MB`;
-}
-
 const styles = StyleSheet.create((theme) => ({
   chrome: {
     flexShrink: 0,
@@ -132,31 +48,11 @@ const styles = StyleSheet.create((theme) => ({
     gap: theme.spacing[3],
     paddingHorizontal: theme.spacing[3],
   },
-  metadata: {
-    flex: 1,
-    minWidth: 0,
-    flexDirection: "row",
-    alignItems: "center",
-    gap: theme.spacing[2],
-  },
-  secondary: { color: theme.colors.foregroundMuted, fontSize: theme.fontSize.sm },
-  whisper: { color: theme.colors.foregroundExtraMuted, fontSize: theme.fontSize.sm },
-  error: { color: theme.colors.palette.red[300], fontSize: theme.fontSize.sm },
-  dirtyDot: {
+  spacer: { flex: 1 },
+  modifiedDot: {
     width: 6,
     height: 6,
     borderRadius: theme.borderRadius.full,
     backgroundColor: theme.colors.foregroundExtraMuted,
   },
-  status: {
-    flexShrink: 0,
-    flexDirection: "row",
-    alignItems: "center",
-    gap: theme.spacing[2],
-  },
-  vim: {
-    color: theme.colors.foregroundMuted,
-    fontFamily: theme.fontFamily.mono,
-    fontSize: theme.fontSize.sm,
-  },
 }));

packages/app/src/file-pane/editor/model.test.ts

@@ -1,652 +0,0 @@
-import { describe, expect, test } from "vitest";
-import type { FileVersion, FileWriteResult } from "@getpaseo/protocol/messages";
-import {
-  FileEditorModel,
-  getFileConflictCallout,
-  type FileEditorClock,
-  type FileEditorFile,
-  type FileEditorObservation,
-  type FileEditorSession,
-  type FileObservationSource,
-} from "./model";
-
-class TestClock implements FileEditorClock {
-  private callback: (() => void) | null = null;
-
-  setTimeout(callback: () => void): ReturnType<typeof setTimeout> {
-    this.callback = callback;
-    return 1 as unknown as ReturnType<typeof setTimeout>;
-  }
-
-  clearTimeout(): void {
-    this.callback = null;
-  }
-
-  fire(): void {
-    const callback = this.callback;
-    this.callback = null;
-    callback?.();
-  }
-}
-
-class FileSession implements FileEditorSession {
-  file: FileEditorFile;
-  writes: Array<{ content: string; expectedModifiedAt: string; expectedRevision?: string }> = [];
-  nextWrite: FileWriteResult | Error | null = null;
-  private pendingWrite: Promise<FileWriteResult> | null = null;
-  private resolvePendingWrite: ((result: FileWriteResult) => void) | null = null;
-
-  constructor(file: FileEditorFile) {
-    this.file = file;
-  }
-
-  async write(input: {
-    content: string;
-    expectedModifiedAt: string;
-    expectedRevision?: string;
-  }): Promise<FileWriteResult> {
-    this.writes.push(input);
-    if (this.pendingWrite) return this.pendingWrite;
-    if (this.nextWrite instanceof Error) throw this.nextWrite;
-    if (this.nextWrite) return this.nextWrite;
-    return {
-      status: "written",
-      modifiedAt: "2026-07-18T00:00:01.000Z",
-      size: input.content.length,
-    };
-  }
-
-  holdNextWrite(): void {
-    this.pendingWrite = new Promise((resolve) => {
-      this.resolvePendingWrite = resolve;
-    });
-  }
-
-  finishHeldWrite(result: FileWriteResult): void {
-    this.resolvePendingWrite?.(result);
-    this.pendingWrite = null;
-    this.resolvePendingWrite = null;
-  }
-}
-
-class ObservationSource implements FileObservationSource {
-  observation: FileEditorObservation | null;
-  refreshes = 0;
-  private readonly listeners = new Set<() => void>();
-
-  constructor(observation: FileEditorObservation | null) {
-    this.observation = observation;
-  }
-
-  subscribe(listener: () => void): () => void {
-    this.listeners.add(listener);
-    return () => this.listeners.delete(listener);
-  }
-
-  getObservation(): FileEditorObservation | null {
-    return this.observation;
-  }
-
-  refresh = (): void => {
-    this.refreshes += 1;
-  };
-
-  emit(observation: FileEditorObservation): void {
-    this.observation = observation;
-    for (const listener of this.listeners) listener();
-  }
-}
-
-function ready(
-  modifiedAt = "2026-07-18T00:00:00.000Z",
-  size = 3,
-): Extract<FileVersion, { status: "ready" }> {
-  return { status: "ready", cwd: "/workspace", path: "file.ts", size, modifiedAt };
-}
-
-interface MakeModelInput {
-  content?: string;
-  hasBom?: boolean;
-}
-
-function makeModel(input: MakeModelInput = {}) {
-  const file = {
-    content: input.content ?? "one",
-    hasBom: input.hasBom ?? false,
-    version: ready() as Extract<FileVersion, { status: "ready" }>,
-  };
-  const session = new FileSession(file);
-  const clock = new TestClock();
-  return { model: new FileEditorModel({ file, session, clock }), session, clock };
-}
-
-function observeFile(model: FileEditorModel, file: FileEditorFile): void {
-  model.receiveFileObservation({ status: "ready", file });
-}
-
-function observeVersion(model: FileEditorModel, version: FileEditorObservation): void {
-  model.receiveFileObservation(version);
-}
-
-describe("FileEditorModel", () => {
-  test("tracks whether the current buffer differs from persisted content", async () => {
-    const { model } = makeModel();
-
-    expect(model.getSnapshot().modified).toBe(false);
-    model.edit("two");
-    expect(model.getSnapshot().modified).toBe(true);
-    model.edit("one");
-    expect(model.getSnapshot()).toMatchObject({ status: "clean", modified: false });
-
-    model.edit("saved");
-    await model.save();
-    expect(model.getSnapshot()).toMatchObject({ status: "clean", modified: false });
-  });
-
-  test("adopts a precise revision for otherwise unchanged initial metadata", () => {
-    const { model } = makeModel();
-
-    observeFile(model, {
-      content: "one",
-      hasBom: false,
-      version: { ...ready(), revision: "precise-revision" },
-    });
-
-    expect(model.getSnapshot().observedVersion).toMatchObject({ revision: "precise-revision" });
-  });
-
-  test("adopts an unchanged disk revision without disturbing a dirty buffer", async () => {
-    const { model, session } = makeModel();
-    model.edit("local");
-    observeFile(model, {
-      content: "one",
-      hasBom: false,
-      version: { ...ready(), revision: "replacement-revision" },
-    });
-
-    expect(model.getSnapshot()).toMatchObject({ status: "dirty", content: "local" });
-    await model.save();
-
-    expect(session.writes).toEqual([
-      {
-        content: "local",
-        expectedModifiedAt: "2026-07-18T00:00:00.000Z",
-        expectedRevision: "replacement-revision",
-      },
-    ]);
-  });
-
-  test("adopts an external BOM change before saving a dirty buffer", async () => {
-    const { model, session } = makeModel();
-    model.edit("local");
-    observeFile(model, {
-      content: "one",
-      hasBom: true,
-      version: { ...ready(), revision: "replacement-revision" },
-    });
-
-    await model.save();
-
-    expect(session.writes).toEqual([
-      {
-        content: "\uFEFFlocal",
-        expectedModifiedAt: "2026-07-18T00:00:00.000Z",
-        expectedRevision: "replacement-revision",
-      },
-    ]);
-  });
-
-  test("conflicts when a same-content observation changes the BOM during a save", async () => {
-    const { model, session } = makeModel();
-    session.holdNextWrite();
-    model.edit("saved");
-    const save = model.save();
-    observeFile(model, {
-      content: "saved",
-      hasBom: true,
-      version: ready("2026-07-18T00:00:02.000Z", 6),
-    });
-    session.finishHeldWrite({
-      status: "written",
-      modifiedAt: "2026-07-18T00:00:01.000Z",
-      size: 5,
-    });
-
-    await save;
-
-    expect(model.getSnapshot()).toMatchObject({
-      status: "conflict",
-      observedVersion: { modifiedAt: "2026-07-18T00:00:02.000Z" },
-    });
-  });
-
-  test("ignores a settled observation that was already consumed", () => {
-    const { model } = makeModel();
-    const observation: FileEditorObservation = {
-      status: "ready",
-      file: { content: "one", hasBom: false, version: ready() },
-    };
-    let emissions = 0;
-    model.subscribe(() => {
-      emissions += 1;
-    });
-    model.receiveFileObservation(observation);
-    const emissionsAfterFirstDelivery = emissions;
-
-    model.receiveFileObservation(observation);
-
-    expect(emissions).toBe(emissionsAfterFirstDelivery);
-  });
-
-  test("does not replay the pre-save observation while its refresh is pending", async () => {
-    const { model } = makeModel();
-    const observation: FileEditorObservation = {
-      status: "ready",
-      file: { content: "one", hasBom: false, version: ready() },
-    };
-    model.receiveFileObservation(observation);
-    model.edit("saved");
-    await model.save();
-
-    model.receiveFileObservation(observation);
-
-    expect(model.getSnapshot()).toMatchObject({ status: "clean", content: "saved" });
-  });
-
-  test("does not reload stale bytes after a write conflict", async () => {
-    const { model, session } = makeModel();
-    session.nextWrite = {
-      status: "conflict",
-      version: ready("2026-07-18T00:00:02.000Z", 8),
-    };
-    model.edit("important local work");
-    await model.save();
-
-    await model.reload();
-
-    expect(model.getSnapshot()).toMatchObject({
-      status: "conflict",
-      content: "important local work",
-      observedVersion: { modifiedAt: "2026-07-18T00:00:02.000Z" },
-    });
-  });
-
-  test("reloads a write conflict only after refreshed bytes arrive", async () => {
-    const { model, session } = makeModel();
-    const source = new ObservationSource({
-      status: "ready",
-      file: { content: "one", hasBom: false, version: ready() },
-    });
-    model.connectFileObservations(source);
-    session.nextWrite = {
-      status: "conflict",
-      version: ready("2026-07-18T00:00:02.000Z", 4),
-    };
-    model.edit("local");
-    await model.save();
-
-    await model.reload();
-    expect(source.refreshes).toBe(1);
-    expect(model.getSnapshot().content).toBe("local");
-    source.emit({
-      status: "ready",
-      file: {
-        content: "disk",
-        hasBom: false,
-        version: ready("2026-07-18T00:00:02.000Z", 4),
-      },
-    });
-
-    expect(model.getSnapshot()).toMatchObject({ status: "clean", content: "disk" });
-  });
-
-  test("abandons a deferred reload when its refresh fails", async () => {
-    const { model, session } = makeModel();
-    const source = new ObservationSource({
-      status: "ready",
-      file: { content: "one", hasBom: false, version: ready() },
-    });
-    model.connectFileObservations(source);
-    session.nextWrite = {
-      status: "conflict",
-      version: ready("2026-07-18T00:00:02.000Z", 4),
-    };
-    model.edit("local");
-    await model.save();
-    await model.reload();
-    source.emit({
-      status: "error",
-      cwd: "/workspace",
-      path: "file.ts",
-      error: "File unavailable.",
-    });
-    model.edit("new local work");
-
-    source.emit({
-      status: "ready",
-      file: {
-        content: "disk",
-        hasBom: false,
-        version: ready("2026-07-18T00:00:03.000Z", 4),
-      },
-    });
-
-    expect(model.getSnapshot()).toMatchObject({ status: "conflict", content: "new local work" });
-  });
-
-  test("keeps a newer edit modified when an older save finishes", async () => {
-    const { model, session } = makeModel();
-    session.holdNextWrite();
-    model.edit("saving");
-
-    const save = model.save();
-    model.edit("newer edit");
-    session.finishHeldWrite({
-      status: "written",
-      modifiedAt: "2026-07-18T00:00:01.000Z",
-      size: 6,
-    });
-    await save;
-
-    expect(model.getSnapshot()).toMatchObject({
-      status: "dirty",
-      content: "newer edit",
-      modified: true,
-    });
-  });
-
-  test("autosaves the latest edit after inactivity", async () => {
-    const { model, session, clock } = makeModel();
-
-    model.edit("two");
-    model.edit("three");
-    clock.fire();
-    await Promise.resolve();
-
-    expect(session.writes).toEqual([
-      { content: "three", expectedModifiedAt: "2026-07-18T00:00:00.000Z" },
-    ]);
-    expect(model.getSnapshot().status).toBe("clean");
-  });
-
-  test("keeps CRLF content in file form", async () => {
-    const { model, session } = makeModel({ content: "one\r\ntwo\r\n" });
-
-    expect(model.getSnapshot()).toMatchObject({
-      content: "one\r\ntwo\r\n",
-      lineSeparator: "\r\n",
-    });
-    model.edit("one\r\ntwo\r\nthree\r\n");
-    await model.save();
-
-    expect(session.writes).toEqual([
-      {
-        content: "one\r\ntwo\r\nthree\r\n",
-        expectedModifiedAt: "2026-07-18T00:00:00.000Z",
-      },
-    ]);
-  });
-
-  test("restores a UTF-8 BOM before writing a CRLF file", async () => {
-    const { model, session } = makeModel({ content: "one\r\n", hasBom: true });
-
-    model.edit("saved\r\n");
-    await model.save();
-    model.edit("saved again\r\n");
-    await model.save();
-
-    expect(session.writes).toEqual([
-      {
-        content: "\uFEFFsaved\r\n",
-        expectedModifiedAt: "2026-07-18T00:00:00.000Z",
-      },
-      {
-        content: "\uFEFFsaved again\r\n",
-        expectedModifiedAt: "2026-07-18T00:00:01.000Z",
-      },
-    ]);
-  });
-
-  test("uses the first line separator when a file mixes styles", () => {
-    const { model } = makeModel({ content: "one\r\ntwo\nthree\r" });
-
-    expect(model.getSnapshot().lineSeparator).toBe("\r\n");
-  });
-
-  test("reloads a clean editor when the disk version changes", async () => {
-    const { model, session } = makeModel();
-    session.file = {
-      content: "external",
-      hasBom: false,
-      version: ready("2026-07-18T00:00:02.000Z", 8) as Extract<FileVersion, { status: "ready" }>,
-    };
-
-    observeFile(model, session.file);
-
-    expect(model.getSnapshot()).toMatchObject({ status: "clean", content: "external" });
-  });
-
-  test("adopts the format from a clean remote refresh", async () => {
-    const { model, session } = makeModel({ content: "local\r\n", hasBom: true });
-    session.file = {
-      content: "remote\n",
-      hasBom: false,
-      version: ready("2026-07-18T00:00:02.000Z", 7) as Extract<FileVersion, { status: "ready" }>,
-    };
-
-    observeFile(model, session.file);
-    expect(model.getSnapshot().lineSeparator).toBe("\n");
-    model.edit("saved\n");
-    await model.save();
-
-    expect(session.writes.at(-1)).toEqual({
-      content: "saved\n",
-      expectedModifiedAt: "2026-07-18T00:00:02.000Z",
-    });
-  });
-
-  test("applies consecutive clean disk observations", () => {
-    const { model } = makeModel();
-    const firstVersion = ready("2026-07-18T00:00:02.000Z", 5);
-    const latestVersion = ready("2026-07-18T00:00:03.000Z", 6);
-
-    observeFile(model, { content: "first", hasBom: false, version: firstVersion });
-    observeFile(model, { content: "latest", hasBom: false, version: latestVersion });
-
-    expect(model.getSnapshot()).toMatchObject({ status: "clean", content: "latest" });
-  });
-
-  test("preserves a dirty buffer and overwrites against the newest disk revision", async () => {
-    const { model, session } = makeModel();
-    model.edit("local");
-    observeFile(model, {
-      content: "disk",
-      hasBom: false,
-      version: ready("2026-07-18T00:00:02.000Z", 4),
-    });
-
-    expect(model.getSnapshot()).toMatchObject({ status: "conflict", content: "local" });
-    await model.overwrite();
-
-    expect(session.writes).toEqual([
-      { content: "local", expectedModifiedAt: "2026-07-18T00:00:02.000Z" },
-    ]);
-    expect(model.getSnapshot().status).toBe("clean");
-  });
-
-  test("keeps the local CRLF and BOM when overwriting a conflict", async () => {
-    const { model, session } = makeModel({ content: "one\r\n", hasBom: true });
-    model.edit("local\r\n");
-    observeFile(model, {
-      content: "disk",
-      hasBom: false,
-      version: ready("2026-07-18T00:00:02.000Z", 4),
-    });
-
-    await model.overwrite();
-
-    expect(session.writes).toEqual([
-      {
-        content: "\uFEFFlocal\r\n",
-        expectedModifiedAt: "2026-07-18T00:00:02.000Z",
-      },
-    ]);
-  });
-
-  test("reload discards a conflicted local buffer for the disk contents", async () => {
-    const { model, session } = makeModel();
-    model.edit("local");
-    const diskVersion = ready("2026-07-18T00:00:02.000Z", 4) as Extract<
-      FileVersion,
-      { status: "ready" }
-    >;
-    session.file = { content: "disk", hasBom: false, version: diskVersion };
-    observeFile(model, session.file);
-
-    await model.reload();
-
-    expect(model.getSnapshot()).toMatchObject({ status: "clean", content: "disk" });
-  });
-
-  test("adopts the remote format when reloading a conflict", async () => {
-    const { model, session } = makeModel({ content: "one\r\n", hasBom: true });
-    model.edit("local\r\n");
-    const diskVersion = ready("2026-07-18T00:00:02.000Z", 5) as Extract<
-      FileVersion,
-      { status: "ready" }
-    >;
-    session.file = { content: "disk\n", hasBom: false, version: diskVersion };
-    observeFile(model, session.file);
-
-    await model.reload();
-    model.edit("saved\n");
-    await model.save();
-
-    expect(session.writes.at(-1)).toEqual({
-      content: "saved\n",
-      expectedModifiedAt: "2026-07-18T00:00:02.000Z",
-    });
-  });
-
-  test("reports failed saves without losing the local buffer", async () => {
-    const { model, session } = makeModel();
-    session.nextWrite = new Error("disk full");
-    model.edit("important local work");
-
-    await model.save();
-
-    expect(model.getSnapshot()).toMatchObject({
-      status: "error",
-      content: "important local work",
-      error: "disk full",
-    });
-  });
-
-  test("a deletion conflicts with local changes and stops autosave", () => {
-    const { model, session, clock } = makeModel();
-    model.edit("local");
-    observeVersion(model, { status: "missing", cwd: "/workspace", path: "file.ts" });
-
-    clock.fire();
-
-    expect(model.getSnapshot().status).toBe("conflict");
-    expect(session.writes).toEqual([]);
-  });
-
-  test("clears a transient check error when the recovered file is unchanged", () => {
-    const { model } = makeModel();
-    observeVersion(model, {
-      status: "error",
-      cwd: "/workspace",
-      path: "file.ts",
-      error: "Requested path is not a file",
-    });
-
-    observeFile(model, { content: "one", hasBom: false, version: ready() });
-
-    expect(model.getSnapshot()).toMatchObject({
-      status: "clean",
-      modified: false,
-      observedVersion: { status: "ready" },
-      error: null,
-    });
-  });
-
-  test("resumes autosave when a dirty file recovers unchanged from a check error", async () => {
-    const { model, session, clock } = makeModel();
-    model.edit("local");
-    observeVersion(model, {
-      status: "error",
-      cwd: "/workspace",
-      path: "file.ts",
-      error: "Requested path is not a file",
-    });
-
-    observeFile(model, { content: "one", hasBom: false, version: ready() });
-    clock.fire();
-    await Promise.resolve();
-
-    expect(model.getSnapshot()).toMatchObject({ status: "clean", modified: false });
-    expect(session.writes).toEqual([
-      { content: "local", expectedModifiedAt: "2026-07-18T00:00:00.000Z" },
-    ]);
-  });
-
-  test("dispose cancels pending autosave", () => {
-    const { model, session, clock } = makeModel();
-    model.edit("local");
-
-    model.dispose();
-    clock.fire();
-
-    expect(session.writes).toEqual([]);
-  });
-
-  test("suspends a pending autosave while close confirmation is active", async () => {
-    const { model, session, clock } = makeModel();
-    model.edit("local");
-
-    const resume = model.suspendAutosave();
-    clock.fire();
-    expect(session.writes).toEqual([]);
-
-    resume();
-    clock.fire();
-    await Promise.resolve();
-    expect(session.writes).toHaveLength(1);
-  });
-
-  test("maps conflict versions to one exhaustive callout state", () => {
-    const { model } = makeModel();
-    const snapshot = model.getSnapshot();
-
-    expect(getFileConflictCallout(snapshot)).toBeNull();
-    expect(
-      getFileConflictCallout({
-        ...snapshot,
-        status: "conflict",
-        modified: true,
-        observedVersion: ready("2026-07-18T00:00:01.000Z"),
-      }),
-    ).toEqual({ kind: "changed", canOverwrite: true });
-    expect(
-      getFileConflictCallout({
-        ...snapshot,
-        status: "conflict",
-        observedVersion: { status: "missing", cwd: "/workspace", path: "file.ts" },
-      }),
-    ).toEqual({ kind: "deleted" });
-    expect(
-      getFileConflictCallout({
-        ...snapshot,
-        status: "conflict",
-        observedVersion: {
-          status: "error",
-          cwd: "/workspace",
-          path: "file.ts",
-          error: "unreadable",
-        },
-      }),
-    ).toEqual({ kind: "checkFailed" });
-  });
-});

packages/app/src/file-pane/editor/model.ts

@@ -1,402 +0,0 @@
-import type { FileVersion, FileWriteResult } from "@getpaseo/protocol/messages";
-
-export type FileEditorStatus = "clean" | "dirty" | "saving" | "conflict" | "error";
-export type FileLineSeparator = "\n" | "\r\n" | "\r";
-
-export interface FileEditorSnapshot {
-  status: FileEditorStatus;
-  content: string;
-  lineSeparator: FileLineSeparator;
-  modified: boolean;
-  version: FileVersion;
-  observedVersion: FileVersion;
-  error: string | null;
-}
-
-export type FileConflictCallout =
-  | { kind: "changed"; canOverwrite: boolean }
-  | { kind: "deleted" }
-  | { kind: "checkFailed" };
-
-export interface FileEditorFile {
-  content: string;
-  hasBom: boolean;
-  version: Extract<FileVersion, { status: "ready" }>;
-}
-
-export interface FileEditorSession {
-  write(input: {
-    content: string;
-    expectedModifiedAt: string;
-    expectedRevision?: string;
-  }): Promise<FileWriteResult>;
-}
-
-export type FileEditorObservation =
-  | { status: "ready"; file: FileEditorFile }
-  | Extract<FileVersion, { status: "missing" | "error" }>;
-
-export interface FileObservationSource {
-  subscribe(listener: () => void): () => void;
-  getObservation(): FileEditorObservation | null;
-  refresh(): void;
-}
-
-type ObservedDiskState = FileEditorObservation | { status: "unsettled"; version: FileVersion };
-
-export interface FileEditorClock {
-  setTimeout(callback: () => void, delayMs: number): ReturnType<typeof setTimeout>;
-  clearTimeout(handle: ReturnType<typeof setTimeout>): void;
-}
-
-const systemClock: FileEditorClock = {
-  setTimeout(callback, delay) {
-    return globalThis.setTimeout(callback, delay);
-  },
-  clearTimeout(handle) {
-    globalThis.clearTimeout(handle);
-  },
-};
-
-export class FileEditorModel {
-  private readonly session: FileEditorSession;
-  private readonly clock: FileEditorClock;
-  private readonly listeners = new Set<() => void>();
-  private snapshot: FileEditorSnapshot;
-  private autosave: ReturnType<typeof setTimeout> | null = null;
-  private saveSequence = 0;
-  private disposed = false;
-  private observedWhileSaving: FileEditorObservation | null = null;
-  private observed: ObservedDiskState;
-  private lastReceivedObservation: FileEditorObservation | null = null;
-  private refreshObservation: (() => void) | null = null;
-  private reloadRequested = false;
-  private persistedContent: string;
-  private hasBom: boolean;
-  private unsubscribeObservationSource: (() => void) | null = null;
-
-  constructor(input: {
-    file: FileEditorFile;
-    session: FileEditorSession;
-    clock?: FileEditorClock;
-  }) {
-    this.session = input.session;
-    this.clock = input.clock ?? systemClock;
-    this.persistedContent = input.file.content;
-    this.hasBom = input.file.hasBom;
-    this.observed = { status: "ready", file: input.file };
-    this.snapshot = {
-      status: "clean",
-      content: input.file.content,
-      lineSeparator: detectLineSeparator(input.file.content),
-      modified: false,
-      version: input.file.version,
-      observedVersion: input.file.version,
-      error: null,
-    };
-  }
-
-  subscribe = (listener: () => void): (() => void) => {
-    this.listeners.add(listener);
-    return () => this.listeners.delete(listener);
-  };
-
-  getSnapshot = (): FileEditorSnapshot => this.snapshot;
-
-  connectFileObservations(source: FileObservationSource): void {
-    this.disconnectFileObservations();
-    this.refreshObservation = source.refresh;
-    const receiveObservation = () => {
-      const observation = source.getObservation();
-      if (observation) this.receiveFileObservation(observation);
-    };
-    this.unsubscribeObservationSource = source.subscribe(receiveObservation);
-    receiveObservation();
-  }
-
-  disconnectFileObservations(): void {
-    this.unsubscribeObservationSource?.();
-    this.unsubscribeObservationSource = null;
-    this.refreshObservation = null;
-  }
-
-  edit(content: string): void {
-    if (this.disposed || content === this.snapshot.content) return;
-    this.reloadRequested = false;
-    const modified = content !== this.persistedContent;
-    let status: FileEditorStatus = modified ? "dirty" : "clean";
-    if (this.snapshot.status === "conflict") {
-      status = "conflict";
-    }
-    this.setSnapshot({ ...this.snapshot, status, content, modified, error: null });
-    if (status === "dirty") this.scheduleAutosave();
-    else this.clearAutosave();
-  }
-
-  async save(): Promise<void> {
-    if (this.disposed || (this.snapshot.status !== "dirty" && this.snapshot.status !== "error")) {
-      return;
-    }
-    if (this.snapshot.observedVersion.status !== "ready") {
-      this.enterConflict(this.snapshot.observedVersion);
-      return;
-    }
-    await this.performWrite(this.snapshot.observedVersion);
-  }
-
-  receiveFileObservation(observation: FileEditorObservation): void {
-    if (this.disposed || observation === this.lastReceivedObservation) return;
-    this.lastReceivedObservation = observation;
-    const version = observationVersion(observation);
-    this.observed = observation;
-    this.setSnapshot({ ...this.snapshot, observedVersion: version });
-    if (this.snapshot.status === "saving") {
-      this.observedWhileSaving = observation;
-      return;
-    }
-    if (observation.status !== "ready") {
-      this.reloadRequested = false;
-      this.enterConflict(version);
-      return;
-    }
-    if (this.reloadRequested) {
-      this.reloadRequested = false;
-      this.applyFile(observation.file);
-      return;
-    }
-    if (observation.file.content === this.persistedContent) {
-      this.adoptUnchangedFile(observation.file);
-      return;
-    }
-    if (this.snapshot.status === "clean") {
-      this.applyFile(observation.file);
-      return;
-    }
-    this.enterConflict(version);
-  }
-
-  async overwrite(): Promise<void> {
-    if (this.disposed || this.snapshot.status !== "conflict") return;
-    if (this.snapshot.observedVersion.status !== "ready") return;
-    await this.performWrite(this.snapshot.observedVersion);
-  }
-
-  async reload(): Promise<void> {
-    if (this.disposed) return;
-    if (this.observed.status !== "ready") {
-      this.reloadRequested = true;
-      this.refreshObservation?.();
-      return;
-    }
-    this.applyFile(this.observed.file);
-  }
-
-  dispose(): void {
-    this.disposed = true;
-    this.reloadRequested = false;
-    this.saveSequence += 1;
-    this.clearAutosave();
-    this.disconnectFileObservations();
-    this.listeners.clear();
-  }
-
-  suspendAutosave(): () => void {
-    const wasScheduled = this.autosave !== null;
-    this.clearAutosave();
-    let resumed = false;
-    return () => {
-      if (resumed || this.disposed) return;
-      resumed = true;
-      if (wasScheduled && this.snapshot.status === "dirty") this.scheduleAutosave();
-    };
-  }
-
-  private async performWrite(
-    expectedVersion: Extract<FileVersion, { status: "ready" }>,
-  ): Promise<void> {
-    this.clearAutosave();
-    const sequence = ++this.saveSequence;
-    const content = this.snapshot.content;
-    const hasBom = this.hasBom;
-    this.observedWhileSaving = null;
-    this.setSnapshot({ ...this.snapshot, status: "saving", error: null });
-    const serializedContent = hasBom ? `\uFEFF${content}` : content;
-    let result: FileWriteResult;
-    try {
-      result = await this.session.write({
-        content: serializedContent,
-        expectedModifiedAt: expectedVersion.modifiedAt,
-        expectedRevision: expectedVersion.revision,
-      });
-    } catch (error) {
-      if (this.disposed || sequence !== this.saveSequence) return;
-      this.setSnapshot({
-        ...this.snapshot,
-        status: "error",
-        error: error instanceof Error ? error.message : String(error),
-      });
-      return;
-    }
-    if (this.disposed || sequence !== this.saveSequence) return;
-    if (result.status === "error") {
-      this.setSnapshot({ ...this.snapshot, status: "error", error: result.error });
-      return;
-    }
-    if (result.status === "conflict") {
-      this.observed = { status: "unsettled", version: result.version };
-      this.enterConflict(result.version);
-      return;
-    }
-
-    const writtenVersion: Extract<FileVersion, { status: "ready" }> = {
-      status: "ready",
-      cwd: this.snapshot.version.cwd,
-      path: this.snapshot.version.path,
-      size: result.size,
-      modifiedAt: result.modifiedAt,
-      revision: result.revision,
-    };
-    const pending = this.takeObservedWhileSaving();
-    this.persistedContent = content;
-    if (pending && !observationMatchesWrite(pending, content, hasBom)) {
-      const pendingVersion = observationVersion(pending);
-      this.observed = pending;
-      this.setSnapshot({
-        ...this.snapshot,
-        status: "conflict",
-        modified: this.snapshot.content !== this.persistedContent,
-        version: writtenVersion,
-        observedVersion: pendingVersion,
-        error: null,
-      });
-      return;
-    }
-    const settledVersion = pending?.status === "ready" ? pending.file.version : writtenVersion;
-    this.observed = pending ?? { status: "unsettled", version: writtenVersion };
-    const modified = this.snapshot.content !== this.persistedContent;
-    this.setSnapshot({
-      ...this.snapshot,
-      status: modified ? "dirty" : "clean",
-      modified,
-      version: settledVersion,
-      observedVersion: settledVersion,
-      error: null,
-    });
-    if (modified) this.scheduleAutosave();
-  }
-
-  private applyFile(file: FileEditorFile): void {
-    this.clearAutosave();
-    this.saveSequence += 1;
-    this.persistedContent = file.content;
-    this.hasBom = file.hasBom;
-    this.observed = { status: "ready", file };
-    this.setSnapshot({
-      status: "clean",
-      content: file.content,
-      lineSeparator: detectLineSeparator(file.content),
-      modified: false,
-      version: file.version,
-      observedVersion: file.version,
-      error: null,
-    });
-  }
-
-  private takeObservedWhileSaving(): FileEditorObservation | null {
-    const observation = this.observedWhileSaving;
-    this.observedWhileSaving = null;
-    return observation;
-  }
-
-  private enterConflict(version: FileVersion): void {
-    this.clearAutosave();
-    this.setSnapshot({
-      ...this.snapshot,
-      status: "conflict",
-      modified: this.snapshot.content !== this.persistedContent,
-      observedVersion: version,
-      error: version.status === "error" ? version.error : null,
-    });
-  }
-
-  private adoptUnchangedFile(file: FileEditorFile): void {
-    this.hasBom = file.hasBom;
-    this.observed = { status: "ready", file };
-    const modified = this.snapshot.content !== this.persistedContent;
-    const recovering = this.snapshot.status === "conflict";
-    let status = this.snapshot.status;
-    if (recovering) status = modified ? "dirty" : "clean";
-    this.setSnapshot({
-      ...this.snapshot,
-      status,
-      modified,
-      version: file.version,
-      observedVersion: file.version,
-      error: recovering ? null : this.snapshot.error,
-    });
-    if (status === "dirty") this.scheduleAutosave();
-    else this.clearAutosave();
-  }
-
-  private scheduleAutosave(): void {
-    this.clearAutosave();
-    this.autosave = this.clock.setTimeout(() => {
-      this.autosave = null;
-      void this.save();
-    }, 800);
-  }
-
-  private clearAutosave(): void {
-    if (!this.autosave) return;
-    this.clock.clearTimeout(this.autosave);
-    this.autosave = null;
-  }
-
-  private setSnapshot(snapshot: FileEditorSnapshot): void {
-    this.snapshot = snapshot;
-    for (const listener of this.listeners) listener();
-  }
-}
-
-export function getFileConflictCallout(snapshot: FileEditorSnapshot): FileConflictCallout | null {
-  if (snapshot.status !== "conflict") return null;
-  switch (snapshot.observedVersion.status) {
-    case "ready":
-      return { kind: "changed", canOverwrite: snapshot.modified };
-    case "missing":
-      return { kind: "deleted" };
-    case "error":
-      return { kind: "checkFailed" };
-    default:
-      return assertNever(snapshot.observedVersion);
-  }
-}
-
-function assertNever(value: never): never {
-  throw new Error(`Unexpected file version: ${JSON.stringify(value)}`);
-}
-
-function detectLineSeparator(content: string): FileLineSeparator {
-  for (let index = 0; index < content.length; index += 1) {
-    const character = content.charCodeAt(index);
-    if (character === 10) return "\n";
-    if (character === 13) return content.charCodeAt(index + 1) === 10 ? "\r\n" : "\r";
-  }
-  return "\n";
-}
-
-function observationVersion(observation: FileEditorObservation): FileVersion {
-  return observation.status === "ready" ? observation.file.version : observation;
-}
-
-function observationMatchesWrite(
-  observation: FileEditorObservation,
-  content: string,
-  hasBom: boolean,
-): boolean {
-  return (
-    observation.status === "ready" &&
-    observation.file.content === content &&
-    observation.file.hasBom === hasBom
-  );
-}

packages/app/src/file-pane/editor/observation-source.test.ts

@@ -1,60 +0,0 @@
-import type { FileReadResult } from "@getpaseo/client/internal/daemon-client";
-import { describe, expect, test } from "vitest";
-import type { LiveFileObservation } from "../live-file/model";
-import { createFileObservationSource, type LiveObservationSource } from "./observation-source";
-
-class TestLiveObservationSource implements LiveObservationSource {
-  observation: LiveFileObservation | null;
-
-  constructor(observation: LiveFileObservation | null) {
-    this.observation = observation;
-  }
-
-  subscribe(): () => void {
-    return () => undefined;
-  }
-
-  getObservation(): LiveFileObservation | null {
-    return this.observation;
-  }
-
-  refresh(): void {}
-}
-
-function readyObservation(): LiveFileObservation {
-  const file: FileReadResult = {
-    bytes: new TextEncoder().encode("one"),
-    mime: "text/plain",
-    size: 3,
-    path: "file.ts",
-    kind: "text",
-    modifiedAt: "2026-07-18T00:00:00.000Z",
-    revision: "revision-1",
-  };
-  return {
-    status: "ready",
-    file,
-    version: {
-      status: "ready",
-      cwd: "/workspace",
-      path: "file.ts",
-      size: file.size,
-      modifiedAt: file.modifiedAt,
-      revision: file.revision,
-    },
-  };
-}
-
-describe("createFileObservationSource", () => {
-  test("returns the same editor observation until the live observation changes", () => {
-    const liveFile = new TestLiveObservationSource(readyObservation());
-    const source = createFileObservationSource(liveFile);
-
-    const first = source.getObservation();
-    const repeated = source.getObservation();
-
-    expect(repeated).toBe(first);
-    liveFile.observation = readyObservation();
-    expect(source.getObservation()).not.toBe(first);
-  });
-});

packages/app/src/file-pane/editor/observation-source.ts

@@ -1,50 +0,0 @@
-import { explorerFileFromReadResult } from "@/file-explorer/read-result";
-import type { LiveFileObservation } from "../live-file/model";
-import type { FileEditorObservation, FileObservationSource } from "./model";
-
-export interface LiveObservationSource {
-  subscribe(listener: () => void): () => void;
-  getObservation(): LiveFileObservation | null;
-  refresh(): void;
-}
-
-export function createFileObservationSource(
-  liveFile: LiveObservationSource,
-): FileObservationSource {
-  let liveObservation: LiveFileObservation | null = null;
-  let editorObservation: FileEditorObservation | null = null;
-  return {
-    subscribe: liveFile.subscribe,
-    refresh: liveFile.refresh,
-    getObservation() {
-      const nextLiveObservation = liveFile.getObservation();
-      if (nextLiveObservation === liveObservation) return editorObservation;
-      liveObservation = nextLiveObservation;
-      editorObservation = fileEditorObservation(nextLiveObservation);
-      return editorObservation;
-    },
-  };
-}
-
-function fileEditorObservation(
-  observation: LiveFileObservation | null,
-): FileEditorObservation | null {
-  if (!observation || observation.status !== "ready") return observation;
-  const decodedFile = explorerFileFromReadResult(observation.file);
-  if (decodedFile.kind !== "text" || decodedFile.content === undefined) {
-    return {
-      status: "error",
-      cwd: observation.version.cwd,
-      path: observation.version.path,
-      error: "File is no longer text.",
-    };
-  }
-  return {
-    status: "ready",
-    file: {
-      content: decodedFile.content,
-      hasBom: decodedFile.hasBom,
-      version: observation.version,
-    },
-  };
-}

packages/app/src/file-pane/live-file/hook.ts

@@ -1,61 +0,0 @@
-import type { DaemonClient } from "@getpaseo/client/internal/daemon-client";
-import { useEffect, useMemo, useState, useSyncExternalStore } from "react";
-import { LiveFileModel, type LiveFileSession } from "./model";
-import { SOURCE_PRESENTATION_BUDGETS } from "../source/presentation";
-import { isWeb } from "@/constants/platform";
-
-export function useLiveFile(input: {
-  client: DaemonClient | null;
-  cwd: string | null;
-  path: string | null;
-  enabled: boolean;
-  liveUpdates: boolean;
-}) {
-  const [model] = useState(() => new LiveFileModel());
-  const session = useMemo<LiveFileSession | null>(() => {
-    if (!input.client) return null;
-    const client = input.client;
-    return {
-      subscribe(target, onVersion) {
-        return client.subscribeFile(target, onVersion);
-      },
-      read(target) {
-        return client.readFile(
-          target.cwd,
-          target.path,
-          undefined,
-          SOURCE_PRESENTATION_BUDGETS[isWeb ? "web" : "native"].plain,
-        );
-      },
-    };
-  }, [input.client]);
-
-  useEffect(() => {
-    if (!input.enabled || !session || !input.cwd || !input.path) {
-      model.close();
-      return;
-    }
-    model.open({
-      session,
-      target: { cwd: input.cwd, path: input.path },
-      liveUpdates: input.liveUpdates,
-    });
-    return () => model.close();
-  }, [input.cwd, input.enabled, input.liveUpdates, input.path, model, session]);
-
-  const snapshot = useSyncExternalStore(model.subscribe, model.getSnapshot, model.getSnapshot);
-  return {
-    file: snapshot.observation?.status === "ready" ? snapshot.observation.file : null,
-    error: snapshot.read.status === "error" ? snapshot.read.error : null,
-    // Effects start reads after the first render. An enabled target is therefore
-    // already in the producer's initial/retargeting display state.
-    isFetching:
-      input.enabled &&
-      (snapshot.read.status === "pending" ||
-        (snapshot.read.status === "idle" && snapshot.observation === null)),
-    isRetrying: snapshot.read.status === "pending" && snapshot.read.requested,
-    refresh: model.refresh,
-    model,
-    snapshot,
-  };
-}

packages/app/src/file-pane/live-file/model.test.ts

@@ -1,344 +0,0 @@
-import type { FileReadResult } from "@getpaseo/client/internal/daemon-client";
-import type { FileVersion } from "@getpaseo/protocol/messages";
-import { describe, expect, it, vi } from "vitest";
-import { LiveFileModel, type LiveFileSession, type LiveFileSubscription } from "./model";
-
-interface Deferred<T> {
-  promise: Promise<T>;
-  resolve(value: T): void;
-  reject(error: Error): void;
-}
-
-function deferred<T>(): Deferred<T> {
-  let resolve!: (value: T) => void;
-  let reject!: (error: Error) => void;
-  const promise = new Promise<T>((onResolve, onReject) => {
-    resolve = onResolve;
-    reject = onReject;
-  });
-  return { promise, resolve, reject };
-}
-
-function ready(revision = "revision-1"): Extract<FileVersion, { status: "ready" }> {
-  return {
-    status: "ready",
-    cwd: "/workspace",
-    path: "file.ts",
-    size: 3,
-    modifiedAt: "2026-07-30T00:00:00.000Z",
-    revision,
-  };
-}
-
-function file(revision = "revision-1", content = "one"): FileReadResult {
-  return {
-    bytes: new TextEncoder().encode(content),
-    mime: "text/plain",
-    size: content.length,
-    path: "file.ts",
-    kind: "text",
-    modifiedAt: "2026-07-30T00:00:00.000Z",
-    revision,
-  };
-}
-
-class TestLiveFileSession implements LiveFileSession {
-  readonly reads: Deferred<FileReadResult>[] = [];
-  subscribeAttempts = 0;
-  private onVersion: ((version: FileVersion) => void) | null = null;
-  private readonly initial: FileVersion;
-
-  constructor(initial: FileVersion = ready()) {
-    this.initial = initial;
-  }
-
-  async subscribe(
-    _target: { cwd: string; path: string },
-    onVersion: (version: FileVersion) => void,
-  ): Promise<LiveFileSubscription> {
-    this.subscribeAttempts += 1;
-    this.onVersion = onVersion;
-    return { initial: this.initial, unsubscribe: () => (this.onVersion = null) };
-  }
-
-  read(): Promise<FileReadResult> {
-    const request = deferred<FileReadResult>();
-    this.reads.push(request);
-    return request.promise;
-  }
-
-  emit(version: FileVersion): void {
-    this.onVersion?.(version);
-  }
-}
-
-class DeferredSubscribeSession implements LiveFileSession {
-  readonly reads: Deferred<FileReadResult>[] = [];
-  readonly subscription = deferred<LiveFileSubscription>();
-  private onVersion: ((version: FileVersion) => void) | null = null;
-
-  subscribe(
-    _target: { cwd: string; path: string },
-    onVersion: (version: FileVersion) => void,
-  ): Promise<LiveFileSubscription> {
-    this.onVersion = onVersion;
-    return this.subscription.promise;
-  }
-
-  read(): Promise<FileReadResult> {
-    const request = deferred<FileReadResult>();
-    this.reads.push(request);
-    return request.promise;
-  }
-
-  emit(version: FileVersion): void {
-    this.onVersion?.(version);
-  }
-}
-
-class FlakySubscriptionSession extends TestLiveFileSession {
-  override async subscribe(
-    target: { cwd: string; path: string },
-    onVersion: (version: FileVersion) => void,
-  ): Promise<LiveFileSubscription> {
-    if (this.subscribeAttempts === 0) {
-      this.subscribeAttempts += 1;
-      throw new Error("Connection closed.");
-    }
-    return super.subscribe(target, onVersion);
-  }
-}
-
-async function waitForRead(
-  session: { reads: Deferred<FileReadResult>[] },
-  count: number,
-): Promise<void> {
-  await vi.waitFor(() => expect(session.reads).toHaveLength(count));
-}
-
-describe("LiveFileModel", () => {
-  it("reports initial and read-pending work before any terminal observation", async () => {
-    const session = new TestLiveFileSession();
-    const model = new LiveFileModel();
-    model.open({ session, target: { cwd: "/workspace", path: "file.ts" }, liveUpdates: false });
-    await waitForRead(session, 1);
-    expect(model.getSnapshot()).toEqual({
-      observation: null,
-      read: { status: "pending", requested: false },
-    });
-  });
-
-  it("reports read error as terminal and recovers on refresh", async () => {
-    const session = new TestLiveFileSession();
-    const model = new LiveFileModel();
-    model.open({ session, target: { cwd: "/workspace", path: "file.ts" }, liveUpdates: false });
-    await waitForRead(session, 1);
-    session.reads[0].reject(new Error("read failed"));
-    await vi.waitFor(() =>
-      expect(model.getSnapshot().read).toEqual({ status: "error", error: "read failed" }),
-    );
-    model.refresh();
-    await waitForRead(session, 2);
-    session.reads[1].resolve(file("revision-2"));
-    await vi.waitFor(() => expect(model.getObservation()?.status).toBe("ready"));
-  });
-  it("does not publish a missing candidate when the following read succeeds", async () => {
-    const session = new TestLiveFileSession();
-    const model = new LiveFileModel();
-    model.open({
-      session,
-      target: { cwd: "/workspace", path: "file.ts" },
-      liveUpdates: true,
-    });
-    await waitForRead(session, 1);
-    session.reads[0].resolve(file());
-    await vi.waitFor(() => expect(model.getObservation()).toMatchObject({ status: "ready" }));
-    const publishedStatuses: string[] = [];
-    model.subscribe(() => {
-      const observation = model.getObservation();
-      if (observation) publishedStatuses.push(observation.status);
-    });
-
-    session.emit({ status: "missing", cwd: "/workspace", path: "file.ts" });
-    await waitForRead(session, 2);
-    session.reads[1].resolve(file());
-    await vi.waitFor(() => expect(model.getSnapshot().read).toEqual({ status: "idle" }));
-
-    expect(publishedStatuses).not.toContain("missing");
-  });
-
-  it("publishes missing when the following read also fails", async () => {
-    const session = new TestLiveFileSession();
-    const model = new LiveFileModel();
-    model.open({
-      session,
-      target: { cwd: "/workspace", path: "file.ts" },
-      liveUpdates: true,
-    });
-    await waitForRead(session, 1);
-    session.reads[0].resolve(file());
-    await vi.waitFor(() => expect(model.getObservation()?.status).toBe("ready"));
-
-    session.emit({ status: "missing", cwd: "/workspace", path: "file.ts" });
-    await waitForRead(session, 2);
-    session.reads[1].reject(new Error("File not found."));
-
-    await vi.waitFor(() => expect(model.getObservation()?.status).toBe("missing"));
-  });
-
-  it("preserves a missing candidate for its queued confirming read", async () => {
-    const session = new TestLiveFileSession();
-    const model = new LiveFileModel();
-    model.open({
-      session,
-      target: { cwd: "/workspace", path: "file.ts" },
-      liveUpdates: true,
-    });
-    await waitForRead(session, 1);
-
-    session.emit({ status: "missing", cwd: "/workspace", path: "file.ts" });
-    session.reads[0].resolve(file());
-    await waitForRead(session, 2);
-    session.reads[1].reject(new Error("File not found."));
-
-    await vi.waitFor(() => expect(model.getObservation()?.status).toBe("missing"));
-  });
-
-  it("recovers only from a read begun after a missing observation", async () => {
-    const session = new TestLiveFileSession();
-    const model = new LiveFileModel();
-    model.open({
-      session,
-      target: { cwd: "/workspace", path: "file.ts" },
-      liveUpdates: true,
-    });
-    await waitForRead(session, 1);
-    session.reads[0].resolve(file());
-    await vi.waitFor(() => expect(model.getObservation()).toMatchObject({ status: "ready" }));
-
-    model.refresh();
-    await waitForRead(session, 2);
-    session.emit({ status: "missing", cwd: "/workspace", path: "file.ts" });
-    session.reads[1].resolve(file("revision-2", "two"));
-
-    await waitForRead(session, 3);
-    expect(model.getObservation()?.status).toBe("ready");
-    expect(model.getSnapshot().read).toEqual({ status: "pending", requested: true });
-
-    session.reads[2].resolve(file("revision-2", "two"));
-    await vi.waitFor(() => {
-      expect(model.getSnapshot()).toMatchObject({
-        observation: {
-          status: "ready",
-          version: { revision: "revision-2" },
-          file: { revision: "revision-2" },
-        },
-        read: { status: "idle" },
-      });
-    });
-  });
-
-  it("keeps an actionable error visible while refresh fails", async () => {
-    const session = new TestLiveFileSession();
-    const model = new LiveFileModel();
-    model.open({
-      session,
-      target: { cwd: "/workspace", path: "file.ts" },
-      liveUpdates: true,
-    });
-    await waitForRead(session, 1);
-    session.reads[0].resolve(file());
-    await vi.waitFor(() => expect(model.getObservation()).toMatchObject({ status: "ready" }));
-
-    session.emit({
-      status: "error",
-      cwd: "/workspace",
-      path: "file.ts",
-      error: "Requested path is not a file",
-    });
-    await waitForRead(session, 2);
-    expect(model.getSnapshot().read).toEqual({ status: "pending", requested: false });
-    session.reads[1].reject(new Error("File unavailable."));
-
-    await vi.waitFor(() => {
-      expect(model.getSnapshot()).toMatchObject({
-        observation: { status: "error", error: "Requested path is not a file" },
-        read: { status: "error", error: "File unavailable." },
-      });
-    });
-
-    model.refresh();
-    await waitForRead(session, 3);
-    expect(model.getSnapshot().read).toEqual({ status: "pending", requested: true });
-  });
-
-  it("keeps an update that arrives before the subscription response", async () => {
-    const session = new DeferredSubscribeSession();
-    const model = new LiveFileModel();
-    model.open({
-      session,
-      target: { cwd: "/workspace", path: "file.ts" },
-      liveUpdates: true,
-    });
-
-    session.emit(ready("revision-2"));
-    session.subscription.resolve({ initial: ready("revision-1"), unsubscribe() {} });
-
-    await waitForRead(session, 1);
-    expect(model.getObservation()).toBeNull();
-  });
-
-  it("retries a failed subscription when the user refreshes", async () => {
-    const session = new FlakySubscriptionSession();
-    const model = new LiveFileModel();
-    model.open({
-      session,
-      target: { cwd: "/workspace", path: "file.ts" },
-      liveUpdates: true,
-    });
-    await waitForRead(session, 1);
-    expect(session.subscribeAttempts).toBe(1);
-
-    session.reads[0].resolve(file());
-    await vi.waitFor(() => expect(model.getObservation()?.status).toBe("ready"));
-    model.refresh();
-
-    await waitForRead(session, 2);
-    expect(session.subscribeAttempts).toBe(2);
-    expect(model.getSnapshot().read).toEqual({ status: "pending", requested: true });
-  });
-
-  it("reads once without subscribing when live updates are disabled", async () => {
-    const session = new TestLiveFileSession();
-    const model = new LiveFileModel();
-    model.open({
-      session,
-      target: { cwd: "/workspace", path: "file.ts" },
-      liveUpdates: false,
-    });
-
-    await waitForRead(session, 1);
-    expect(session.subscribeAttempts).toBe(0);
-    expect(model.getSnapshot().read).toEqual({ status: "pending", requested: false });
-  });
-
-  it("ignores a read that completes after the model closes", async () => {
-    const session = new TestLiveFileSession();
-    const model = new LiveFileModel();
-    model.open({
-      session,
-      target: { cwd: "/workspace", path: "file.ts" },
-      liveUpdates: true,
-    });
-    await waitForRead(session, 1);
-
-    model.close();
-    session.reads[0].resolve(file());
-    await Promise.resolve();
-
-    expect(model.getSnapshot()).toEqual({
-      observation: null,
-      read: { status: "idle" },
-    });
-  });
-});

packages/app/src/file-pane/live-file/model.ts

@@ -1,272 +0,0 @@
-import type { FileReadResult } from "@getpaseo/client/internal/daemon-client";
-import type { FileVersion } from "@getpaseo/protocol/messages";
-
-export interface LiveFileTarget {
-  cwd: string;
-  path: string;
-}
-
-export interface LiveFileSubscription {
-  initial: FileVersion;
-  unsubscribe(): void;
-}
-
-export interface LiveFileSession {
-  subscribe(
-    target: LiveFileTarget,
-    onVersion: (version: FileVersion) => void,
-  ): Promise<LiveFileSubscription>;
-  read(target: LiveFileTarget): Promise<FileReadResult>;
-}
-
-export type LiveFileReadState =
-  | { status: "idle" }
-  | { status: "pending"; requested: boolean }
-  | { status: "error"; error: string };
-
-export type LiveFileObservation =
-  | {
-      status: "ready";
-      version: Extract<FileVersion, { status: "ready" }>;
-      file: FileReadResult;
-    }
-  | Extract<FileVersion, { status: "missing" | "error" }>;
-
-export interface LiveFileSnapshot {
-  observation: LiveFileObservation | null;
-  read: LiveFileReadState;
-}
-
-const idleSnapshot: LiveFileSnapshot = {
-  observation: null,
-  read: { status: "idle" },
-};
-
-export class LiveFileModel {
-  private readonly listeners = new Set<() => void>();
-  private snapshot: LiveFileSnapshot = idleSnapshot;
-  private session: LiveFileSession | null = null;
-  private target: LiveFileTarget | null = null;
-  private liveUpdates = false;
-  private unsubscribe: (() => void) | null = null;
-  private subscriptionPending = false;
-  private generation = 0;
-  private issuedReadSequence = 0;
-  private activeReadSequence: number | null = null;
-  private activeReadRequested = false;
-  private observedAfterReadSequence: number | null = null;
-  private candidateVersion: FileVersion | null = null;
-  private refreshQueued = false;
-  private requestedRefreshQueued = false;
-
-  subscribe = (listener: () => void): (() => void) => {
-    this.listeners.add(listener);
-    return () => this.listeners.delete(listener);
-  };
-
-  getSnapshot = (): LiveFileSnapshot => this.snapshot;
-
-  getObservation = (): LiveFileObservation | null => this.snapshot.observation;
-
-  open(input: { session: LiveFileSession; target: LiveFileTarget; liveUpdates: boolean }): void {
-    this.reset();
-    this.session = input.session;
-    this.target = input.target;
-    this.liveUpdates = input.liveUpdates;
-    const generation = this.generation;
-    if (!input.liveUpdates) {
-      this.scheduleRead(false);
-      return;
-    }
-    void this.startSubscription(generation);
-  }
-
-  close(): void {
-    this.reset();
-  }
-
-  refresh = (): void => {
-    if (!this.session || !this.target) return;
-    if (this.liveUpdates && !this.unsubscribe && !this.subscriptionPending) {
-      void this.startSubscription(this.generation);
-    }
-    this.scheduleRead(true);
-  };
-
-  private scheduleRead(requested: boolean): void {
-    if (this.activeReadSequence !== null) {
-      this.refreshQueued = true;
-      this.activeReadRequested ||= requested;
-      this.requestedRefreshQueued ||= requested;
-      if (requested && this.snapshot.read.status === "pending") {
-        this.setSnapshot({ ...this.snapshot, read: { status: "pending", requested: true } });
-      }
-      return;
-    }
-    this.startRead(requested);
-  }
-
-  private reset(): void {
-    this.generation += 1;
-    this.unsubscribe?.();
-    this.unsubscribe = null;
-    this.session = null;
-    this.target = null;
-    this.liveUpdates = false;
-    this.subscriptionPending = false;
-    this.issuedReadSequence = 0;
-    this.activeReadSequence = null;
-    this.activeReadRequested = false;
-    this.observedAfterReadSequence = null;
-    this.candidateVersion = null;
-    this.refreshQueued = false;
-    this.requestedRefreshQueued = false;
-    this.setSnapshot(idleSnapshot);
-  }
-
-  private async startSubscription(generation: number): Promise<void> {
-    const session = this.session;
-    const target = this.target;
-    if (!session || !target) return;
-    this.subscriptionPending = true;
-    let receivedUpdate = false;
-    try {
-      const subscription = await session.subscribe(target, (version) => {
-        if (generation !== this.generation) return;
-        receivedUpdate = true;
-        this.observeVersion(version);
-      });
-      if (generation !== this.generation) {
-        subscription.unsubscribe();
-        return;
-      }
-      this.subscriptionPending = false;
-      this.unsubscribe = subscription.unsubscribe;
-      if (!receivedUpdate) this.observeVersion(subscription.initial);
-    } catch {
-      if (generation !== this.generation) return;
-      this.subscriptionPending = false;
-      this.scheduleRead(false);
-    }
-  }
-
-  private observeVersion(version: FileVersion): void {
-    this.observedAfterReadSequence = this.issuedReadSequence;
-    this.candidateVersion = version;
-    this.scheduleRead(false);
-  }
-
-  private startRead(requested: boolean): void {
-    const session = this.session;
-    const target = this.target;
-    if (!session || !target) return;
-    const generation = this.generation;
-    const sequence = ++this.issuedReadSequence;
-    this.activeReadSequence = sequence;
-    this.activeReadRequested = requested;
-    this.refreshQueued = false;
-    this.requestedRefreshQueued = false;
-    this.setSnapshot({ ...this.snapshot, read: { status: "pending", requested } });
-    void session.read(target).then(
-      (file) => this.finishRead({ generation, sequence, target, file }),
-      (error) => this.failRead({ generation, sequence, target, error }),
-    );
-  }
-
-  private finishRead(input: {
-    generation: number;
-    sequence: number;
-    target: LiveFileTarget;
-    file: FileReadResult;
-  }): void {
-    if (!this.isActiveRead(input.generation, input.sequence)) return;
-    const requested = this.activeReadRequested;
-    this.activeReadSequence = null;
-    this.activeReadRequested = false;
-    if (this.readPredatesLatestObservation(input.sequence)) {
-      this.startRead(requested || this.takeQueuedRequested());
-      return;
-    }
-    this.observedAfterReadSequence = null;
-    this.candidateVersion = null;
-    this.setSnapshot({
-      observation: {
-        status: "ready",
-        file: input.file,
-        version: readyVersion(input.target, input.file),
-      },
-      read: { status: "idle" },
-    });
-    this.startQueuedRead();
-  }
-
-  private failRead(input: {
-    generation: number;
-    sequence: number;
-    target: LiveFileTarget;
-    error: unknown;
-  }): void {
-    if (!this.isActiveRead(input.generation, input.sequence)) return;
-    const requested = this.activeReadRequested;
-    this.activeReadSequence = null;
-    this.activeReadRequested = false;
-    if (this.readPredatesLatestObservation(input.sequence)) {
-      this.startRead(requested || this.takeQueuedRequested());
-      return;
-    }
-    const message = errorMessage(input.error);
-    const candidate = this.candidateVersion;
-    this.candidateVersion = null;
-    const candidateDescribesFailure =
-      candidate?.status === "missing" || candidate?.status === "error";
-    const observation: LiveFileObservation = candidateDescribesFailure
-      ? candidate
-      : { status: "error", cwd: input.target.cwd, path: input.target.path, error: message };
-    this.setSnapshot({ ...this.snapshot, observation, read: { status: "error", error: message } });
-    this.startQueuedRead();
-  }
-
-  private isActiveRead(generation: number, sequence: number): boolean {
-    return generation === this.generation && sequence === this.activeReadSequence;
-  }
-
-  private readPredatesLatestObservation(sequence: number): boolean {
-    return this.observedAfterReadSequence !== null && sequence <= this.observedAfterReadSequence;
-  }
-
-  private startQueuedRead(): void {
-    if (!this.refreshQueued) return;
-    this.startRead(this.takeQueuedRequested());
-  }
-
-  private takeQueuedRequested(): boolean {
-    const requested = this.requestedRefreshQueued;
-    this.refreshQueued = false;
-    this.requestedRefreshQueued = false;
-    return requested;
-  }
-
-  private setSnapshot(snapshot: LiveFileSnapshot): void {
-    if (snapshot === this.snapshot) return;
-    this.snapshot = snapshot;
-    for (const listener of this.listeners) listener();
-  }
-}
-
-function readyVersion(
-  target: LiveFileTarget,
-  file: FileReadResult,
-): Extract<FileVersion, { status: "ready" }> {
-  return {
-    status: "ready",
-    cwd: target.cwd,
-    path: target.path,
-    size: file.size,
-    modifiedAt: file.modifiedAt,
-    revision: file.revision,
-  };
-}
-
-function errorMessage(error: unknown): string {
-  return error instanceof Error ? error.message : String(error);
-}

packages/app/src/file-pane/pane.tsx

@@ -1,192 +1,27 @@
-import { Button } from "@/components/ui/button";
-import { LoadingSpinner } from "@/components/ui/loading-spinner";
-import React, { useCallback, useEffect, useMemo, useState, useSyncExternalStore } from "react";
-import type { DaemonClient } from "@getpaseo/client/internal/daemon-client";
+import { useEffect, useMemo, useState } from "react";
+import type { PluginFile, PluginFileTab } from "@getpaseo/plugin/client";
 import { Text, View } from "react-native";
-import { StyleSheet, UnistylesRuntime, withUnistyles } from "react-native-unistyles";
+import { StyleSheet } from "react-native-unistyles";
 import { useTranslation } from "react-i18next";
-import { useIsCompactFormFactor } from "@/constants/layout";
-import { useSessionStore, type ExplorerFile } from "@/stores/session-store";
-import { FilePanelPreview, resolveFilePreviewPanel, type FilePanel } from "@/file-panels";
-import { useAttachmentPreviewUrl } from "@/attachments/use-attachment-preview-url";
-import { getFileNameFromPath } from "@/attachments/utils";
-import { resolveFilePreviewReadTarget } from "@/file-explorer/preview-target";
-import type { WorkspaceFileLocation } from "@/workspace/file-open";
+import { Button } from "@/components/ui/button";
 import { useRetainedPanelActive } from "@/components/retained-panel";
+import { useFileHandle, useFileHandleSnapshot } from "@/file-panels/file";
+import { FilePanelLoading } from "@/file-panels/loading";
+import { FilePanelPicker, FilePanelView, useFilePanelChoice, type FilePanel } from "@/file-panels";
+import { resolveFilePreviewReadTarget } from "@/file-explorer/preview-target";
 import { useAppActivelyVisible } from "@/hooks/use-app-visible";
-import { isFileQueryEnabled } from "@/components/file-pane-enabled";
-import { isWeb } from "@/constants/platform";
-import { useAppSettings } from "@/hooks/use-settings";
-import { useLiveFile } from "./live-file/hook";
-import { useFilePreview } from "./preview-lifecycle/hook";
-import { resolveFilePreviewLifecycle } from "./preview-lifecycle/model";
-import { FilePanelBar } from "./bar";
-import { FileEditorModel, getFileConflictCallout, type FileConflictCallout } from "./editor/model";
-import { createFileObservationSource } from "./editor/observation-source";
-import { FileEditorView } from "./editor/view";
-import { FileSourceView } from "./source/view";
-import type { FileConflictAlertState } from "./conflict-alert";
-import type { LiveFileModel } from "./live-file/model";
-import { confirmDialog } from "@/utils/confirm-dialog";
 import { usePublishPanelInstanceAttributes } from "@/panels/panel-instance-attributes";
-import type { Theme } from "@/styles/theme";
-
-const ThemedLoadingSpinner = withUnistyles(LoadingSpinner);
-const foregroundMutedColorMapping = (theme: Theme) => ({
-  color: theme.colors.foregroundMuted,
-});
-
-interface FilePreviewBodyProps {
-  panel: FilePanel | null;
-  preview: ExplorerFile | null;
-  mode?: "preview" | "source";
-  isLoading: boolean;
-  isMobile: boolean;
-  location: WorkspaceFileLocation;
-  navigationRevision: number;
-  imagePreviewUri: string | null;
-  workspaceRoot: string;
-  client: DaemonClient | null;
-  serverId: string;
-}
-
-type TextExplorerFile = ExplorerFile & { kind: "text" };
-
-function trimNonEmpty(value: string | null | undefined): string | null {
-  if (typeof value !== "string") {
-    return null;
-  }
-  const trimmed = value.trim();
-  return trimmed.length > 0 ? trimmed : null;
-}
-
-function formatFileSize({ size }: { size: number }): string {
-  if (size < 1024) {
-    return `${size} B`;
-  }
-  if (size < 1024 * 1024) {
-    return `${(size / 1024).toFixed(1)} KB`;
-  }
-  return `${(size / (1024 * 1024)).toFixed(1)} MB`;
-}
-
-function ReadonlySource({
-  preview,
-  filename,
-  location,
-  navigationRevision,
-}: {
-  preview: ExplorerFile;
-  filename: string;
-  location: WorkspaceFileLocation;
-  navigationRevision: number;
-}) {
-  const theme = UnistylesRuntime.getTheme();
-  const { t } = useTranslation();
-  const visualTheme = useMemo(
-    () => ({
-      colorScheme: theme.colorScheme,
-      background: theme.colors.surface0,
-      foreground: theme.colors.foreground,
-      cursor: theme.colors.terminal.cursor,
-      foregroundMuted: theme.colors.foregroundMuted,
-      border: theme.colors.border,
-      selection: theme.colors.terminal.selectionBackground,
-      monoFont: theme.fontFamily.mono,
-      codeFontSize: theme.fontSize.code,
-      syntax: theme.colors.syntax,
-    }),
-    [theme],
-  );
-  return (
-    <FileSourceView
-      content={preview.content ?? ""}
-      filename={filename}
-      location={location}
-      navigationRevision={navigationRevision}
-      size={preview.size}
-      theme={visualTheme}
-      tooLargeMessage={t("panels.file.tooLargeToDisplay")}
-    />
-  );
-}
-
-function TooLargeSource({ size }: { size?: number }) {
-  const { t } = useTranslation();
-  return (
-    <View style={styles.centerState} testID="file-source-too-large">
-      <Text style={styles.emptyText}>{t("panels.file.tooLargeToDisplay")}</Text>
-      {size ? <Text style={styles.binaryMetaText}>{formatFileSize({ size })}</Text> : null}
-    </View>
-  );
-}
-
-function FilePreviewBody({
-  panel,
-  preview,
-  mode,
-  isLoading,
-  isMobile: _isMobile,
-  location,
-  navigationRevision,
-  imagePreviewUri,
-  workspaceRoot,
-  client,
-  serverId,
-}: FilePreviewBodyProps) {
-  const { t } = useTranslation();
-  const filePath = location.path;
-
-  if (isLoading && !preview) {
-    return (
-      <View style={styles.centerState} testID="file-preview-loading">
-        <ThemedLoadingSpinner size="small" uniProps={foregroundMutedColorMapping} />
-        <Text style={styles.loadingText}>{t("panels.file.loading")}</Text>
-      </View>
-    );
-  }
-
-  if (!preview) {
-    return (
-      <View style={styles.centerState} testID="file-preview-unsupported">
-        <Text style={styles.emptyText}>{t("panels.file.noPreview")}</Text>
-      </View>
-    );
-  }
-
-  const showSource = preview.kind === "text" && (Boolean(location.lineStart) || mode === "source");
-  if (panel && !showSource) {
-    return (
-      <FilePanelPreview
-        panel={panel}
-        content={preview.content ?? ""}
-        filePath={filePath}
-        workspaceRoot={workspaceRoot}
-        client={client}
-        serverId={serverId}
-        imagePreviewUri={imagePreviewUri}
-      />
-    );
-  }
-  if (preview.kind === "text") {
-    return (
-      <ReadonlySource
-        preview={preview}
-        filename={filePath}
-        location={location}
-        navigationRevision={navigationRevision}
-      />
-    );
-  }
-
-  return (
-    <View style={styles.centerState}>
-      <Text style={styles.emptyText}>{t("panels.file.binaryPreviewUnavailable")}</Text>
-      <Text style={styles.binaryMetaText}>{formatFileSize({ size: preview.size })}</Text>
-    </View>
-  );
-}
+import { useSessionStore } from "@/stores/session-store";
+import { buildAbsoluteExplorerPath } from "@/utils/explorer-paths";
+import { formatFileSize } from "@/utils/format-file-size";
+import type { WorkspaceFileLocation } from "@/workspace/file-open";
+import { FilePanelBar } from "./bar";
 
+/**
+ * The file tab: stats the file, picks its panel and mounts it. The panel reads, saves and shows
+ * its own loading; the tab only knows the file exists, its kind, and whether the panel has
+ * unsaved changes.
+ */
 export function FilePane({
   serverId,
   workspaceRoot,
@@ -199,446 +34,120 @@ export function FilePane({
   navigationRevision: number;
 }) {
   const { t } = useTranslation();
-  const { settings } = useAppSettings();
-  const isMobile = useIsCompactFormFactor();
-  const [previewMode, setPreviewMode] = useState<"preview" | "source">("preview");
-
-  const client = useSessionStore((state) => state.sessions[serverId]?.client ?? null);
-  // COMPAT(workspaceFileEditing): added in v0.2.0, remove after 2027-01-18 once daemon floor >= v0.2.0.
-  const supportsEditing = useSessionStore(
-    (state) => state.sessions[serverId]?.serverInfo?.features?.workspaceFileEditing === true,
+  const connected = useSessionStore((state) => Boolean(state.sessions[serverId]?.client));
+  const root = workspaceRoot.trim();
+  const path = location.path.trim();
+  const target = useMemo(
+    () => (path ? resolveFilePreviewReadTarget({ path, workspaceRoot: root }) : null),
+    [path, root],
   );
-  const normalizedWorkspaceRoot = useMemo(() => workspaceRoot.trim(), [workspaceRoot]);
-  const normalizedFilePath = useMemo(() => trimNonEmpty(location.path), [location.path]);
-  const readTarget = useMemo(
-    () =>
-      normalizedFilePath
-        ? resolveFilePreviewReadTarget({
-            path: normalizedFilePath,
-            workspaceRoot: normalizedWorkspaceRoot,
-          })
-        : null,
-    [normalizedFilePath, normalizedWorkspaceRoot],
+  const absolutePath = useMemo(
+    () => buildAbsoluteExplorerPath({ workspaceRoot: root, entryPath: path }),
+    [path, root],
   );
-
-  // Re-read the file when this pane becomes visible again (#445). `isActive`
-  // covers tab switches; active app visibility covers backgrounding and returning
-  // from another window after an external edit. The gate lives in isFileQueryEnabled.
+  // A hidden tab or a backgrounded app stops observing; observing again reports what changed.
   const isActive = useRetainedPanelActive();
   const isAppVisible = useAppActivelyVisible();
-  const enabled = isFileQueryEnabled({
-    hasReadTarget: Boolean(client && readTarget),
-    isTabActive: isActive,
-    isAppVisible,
+  const handle = useFileHandle({
+    serverId,
+    target,
+    absolutePath,
+    observing: isActive && isAppVisible,
   });
-  const liveFile = useLiveFile({
-    client,
-    cwd: readTarget?.cwd ?? null,
-    path: readTarget?.path ?? null,
-    enabled,
-    liveUpdates: supportsEditing,
-  });
-
-  const targetKey = readTarget ? `${readTarget.cwd}:${readTarget.path}` : null;
-  const previewLifecycle = useFilePreview({
+  const snapshot = useFileHandleSnapshot(handle);
+  const targetKey = target ? `${target.cwd}:${target.path}` : null;
+  const { panel, choice } = useFilePanelChoice({
+    serverId,
     targetKey,
-    liveFileSnapshot: liveFile.snapshot,
+    path,
+    fileKind: snapshot.status === "ready" ? snapshot.kind : null,
+    presentable: isActive,
+    lineNavigation: location.lineStart ? navigationRevision : null,
   });
-
-  useEffect(() => setPreviewMode("preview"), [targetKey]);
-
-  const { file: preview, imageAttachment } = resolveFilePreviewLifecycle(previewLifecycle);
-  const imagePreviewUri = useAttachmentPreviewUrl(imageAttachment);
-  const panel = resolveFilePreviewPanel({
-    preview,
-    path: location.path,
-    associations: settings.filePanelAssociations,
-  });
-  const isRenderable = preview?.kind === "text" && panel !== null;
-  const editable = isEditableTextFile({
-    preview,
-    supportsEditing,
-  });
-  const canTogglePreviewMode = isRenderable && !location.lineStart;
-  const lineCount =
-    preview?.kind === "text" ? (preview.content ?? "").split("\n").length : undefined;
-  const errorMessage = previewLifecycle.status === "error" ? previewLifecycle.message : null;
-  const isLoading =
-    previewLifecycle.status === "initial" ||
-    previewLifecycle.status === "read_pending" ||
-    previewLifecycle.status === "preparing";
-
-  return (
-    <FilePanePresentation
-      panel={panel}
-      serverId={serverId}
-      workspaceRoot={normalizedWorkspaceRoot}
-      client={client}
-      readTarget={readTarget}
-      preview={preview}
-      liveFile={liveFile.model}
-      onRetryRead={liveFile.refresh}
-      retryingRead={liveFile.isRetrying}
-      retryLabel={t("common.actions.retry")}
-      filename={getFileNameFromPath(location.path) ?? location.path}
-      previewMode={canTogglePreviewMode ? previewMode : undefined}
-      onPreviewModeChange={canTogglePreviewMode ? setPreviewMode : undefined}
-      lineCount={lineCount}
-      editable={editable}
-      disconnectedMessage={t("workspace.terminal.hostDisconnected")}
-      errorMessage={errorMessage}
-      isLoading={isLoading}
-      isMobile={isMobile}
-      location={location}
-      navigationRevision={navigationRevision}
-      imagePreviewUri={imagePreviewUri}
-    />
+  const [modified, setModified] = useState(false);
+  usePublishPanelInstanceAttributes({ modified, suspendPendingSave: handle?.holdWrites });
+  const panelLocation = useMemo(
+    () => ({
+      lineStart: location.lineStart,
+      lineEnd: location.lineEnd,
+      revision: navigationRevision,
+    }),
+    [location.lineEnd, location.lineStart, navigationRevision],
   );
-}
-
-function isEditableTextFile(input: {
-  preview: ExplorerFile | null;
-  supportsEditing: boolean;
-}): boolean {
-  return Boolean(
-    isWeb &&
-    input.supportsEditing &&
-    input.preview?.kind === "text" &&
-    input.preview.size <= 1024 * 1024,
+  const panelTarget = useMemo(
+    () => ({ serverId, workspaceRoot: root, path }),
+    [path, root, serverId],
   );
-}
 
-function FilePanePresentation({
-  panel,
-  serverId,
-  workspaceRoot,
-  client,
-  readTarget,
-  preview,
-  liveFile,
-  onRetryRead,
-  retryingRead,
-  retryLabel,
-  filename,
-  previewMode,
-  onPreviewModeChange,
-  lineCount,
-  editable,
-  disconnectedMessage,
-  errorMessage,
-  isLoading,
-  isMobile,
-  location,
-  navigationRevision,
-  imagePreviewUri,
-}: {
-  panel: FilePanel | null;
-  serverId: string;
-  workspaceRoot: string;
-  client: DaemonClient | null;
-  readTarget: { cwd: string; path: string } | null;
-  preview: ExplorerFile | null;
-  liveFile: LiveFileModel;
-  onRetryRead: () => void;
-  retryingRead: boolean;
-  retryLabel: string;
-  filename: string;
-  previewMode?: "preview" | "source";
-  onPreviewModeChange?: (mode: "preview" | "source") => void;
-  lineCount?: number;
-  editable: boolean;
-  disconnectedMessage: string;
-  errorMessage: string | null;
-  isLoading: boolean;
-  isMobile: boolean;
-  location: WorkspaceFileLocation;
-  navigationRevision: number;
-  imagePreviewUri: string | null;
-}) {
-  if (!client && readTarget) {
+  let body;
+  if (!connected && target) {
+    body = <Text style={styles.errorText}>{t("workspace.terminal.hostDisconnected")}</Text>;
+  } else if (!handle || snapshot.status === "loading") {
     return (
       <View style={styles.container} testID="workspace-file-pane">
-        <View style={styles.centerState}>
-          <Text style={styles.errorText}>{disconnectedMessage}</Text>
-        </View>
+        <FilePanelLoading />
       </View>
     );
-  }
-
-  if (editable && client && readTarget && preview?.kind === "text") {
-    return (
-      <EditableFilePane
-        panel={panel}
-        key={`${serverId}:${readTarget.cwd}:${readTarget.path}`}
-        serverId={serverId}
-        workspaceRoot={workspaceRoot}
-        client={client}
-        cwd={readTarget.cwd}
-        path={readTarget.path}
-        preview={preview as TextExplorerFile}
-        liveFile={liveFile}
-        onRetryRead={onRetryRead}
-        retryingRead={retryingRead}
-        filename={filename}
-        mode={previewMode}
-        onModeChange={onPreviewModeChange}
-        isLoading={isLoading}
-        isMobile={isMobile}
-        location={location}
-        navigationRevision={navigationRevision}
-      />
+  } else if (snapshot.status === "missing" || snapshot.status === "error") {
+    body = (
+      <>
+        <Text style={styles.errorText}>
+          {snapshot.status === "error" ? snapshot.error : t("panels.file.notFound")}
+        </Text>
+        <Button variant="outline" size="sm" onPress={handle.retry}>
+          {t("common.actions.retry")}
+        </Button>
+      </>
     );
-  }
-
-  if (errorMessage) {
-    if (errorMessage === "File is too large to display") {
-      return (
-        <View style={styles.container} testID="workspace-file-pane">
-          <TooLargeSource />
-        </View>
-      );
-    }
+  } else if (!panel) {
+    body = (
+      <>
+        <Text style={styles.mutedText}>{t("panels.file.binaryPreviewUnavailable")}</Text>
+        <Text style={styles.mutedText}>{formatFileSize(snapshot.size)}</Text>
+      </>
+    );
+  } else {
     return (
       <View style={styles.container} testID="workspace-file-pane">
-        <View style={styles.centerState}>
-          <Text style={styles.errorText}>{errorMessage}</Text>
-          <Button variant="outline" size="sm" onPress={onRetryRead} loading={retryingRead}>
-            {retryLabel}
-          </Button>
-        </View>
-      </View>
-    );
-  }
-
-  return (
-    <View style={styles.container} testID="workspace-file-pane">
-      {preview ? (
-        <FilePanelBar
-          size={preview.size}
-          lineCount={lineCount}
-          mode={previewMode}
-          onModeChange={onPreviewModeChange}
-        />
-      ) : null}
-      <FilePreviewBody
-        panel={panel}
-        preview={preview}
-        mode={previewMode}
-        isLoading={isLoading}
-        isMobile={isMobile}
-        location={location}
-        navigationRevision={navigationRevision}
-        imagePreviewUri={imagePreviewUri}
-        workspaceRoot={workspaceRoot}
-        client={client}
-        serverId={serverId}
-      />
-    </View>
-  );
-}
-
-function EditableFilePane({
-  panel,
-  serverId,
-  workspaceRoot,
-  client,
-  cwd,
-  path,
-  preview,
-  liveFile,
-  onRetryRead,
-  retryingRead,
-  filename,
-  mode,
-  onModeChange,
-  isLoading,
-  isMobile,
-  location,
-  navigationRevision,
-}: {
-  panel: FilePanel | null;
-  serverId: string;
-  workspaceRoot: string;
-  client: DaemonClient;
-  cwd: string;
-  path: string;
-  preview: TextExplorerFile;
-  liveFile: LiveFileModel;
-  onRetryRead: () => void;
-  retryingRead: boolean;
-  filename: string;
-  mode?: "preview" | "source";
-  onModeChange?: (mode: "preview" | "source") => void;
-  isLoading: boolean;
-  isMobile: boolean;
-  location: WorkspaceFileLocation;
-  navigationRevision: number;
-}) {
-  const { settings } = useAppSettings();
-  const { t } = useTranslation();
-  const [cursor, setCursor] = useState({ line: 1, column: 1 });
-  const [vimMode, setVimMode] = useState<string | null>(settings.vimKeybindings ? "NORMAL" : null);
-  const session = useMemo(
-    () => ({
-      write(input: { content: string; expectedModifiedAt: string; expectedRevision?: string }) {
-        return client.writeFile({ cwd, path, ...input });
-      },
-    }),
-    [client, cwd, path],
-  );
-  const [model] = useState(() => {
-    return new FileEditorModel({
-      file: {
-        content: preview.content ?? "",
-        hasBom: preview.hasBom,
-        version: {
-          status: "ready",
-          cwd,
-          path,
-          size: preview.size,
-          modifiedAt: preview.modifiedAt,
-          revision: preview.revision,
-        },
-      },
-      session,
-    });
-  });
-  useEffect(() => {
-    const source = createFileObservationSource(liveFile);
-    model.connectFileObservations(source);
-    return () => model.disconnectFileObservations();
-  }, [liveFile, model]);
-  const snapshot = useSyncExternalStore(model.subscribe, model.getSnapshot, model.getSnapshot);
-  const suspendPendingSave = useCallback(() => model.suspendAutosave(), [model]);
-  usePublishPanelInstanceAttributes({ modified: snapshot.modified, suspendPendingSave });
-  const theme = UnistylesRuntime.getTheme();
-  const visualTheme = useMemo(
-    () => ({
-      colorScheme: theme.colorScheme,
-      background: theme.colors.surface0,
-      foreground: theme.colors.foreground,
-      cursor: theme.colors.terminal.cursor,
-      foregroundMuted: theme.colors.foregroundMuted,
-      border: theme.colors.border,
-      selection: theme.colors.terminal.selectionBackground,
-      monoFont: theme.fontFamily.mono,
-      codeFontSize: theme.fontSize.code,
-      syntax: theme.colors.syntax,
-    }),
-    [
-      theme.colors.border,
-      theme.colors.foreground,
-      theme.colors.foregroundMuted,
-      theme.colors.surface0,
-      theme.colors.syntax,
-      theme.colors.terminal.cursor,
-      theme.colors.terminal.selectionBackground,
-      theme.colorScheme,
-      theme.fontFamily.mono,
-      theme.fontSize.code,
-    ],
-  );
-
-  useEffect(() => () => model.dispose(), [model]);
-
-  const handleReload = useCallback(() => {
-    if (!snapshot.modified) {
-      void model.reload();
-      return;
-    }
-    void (async () => {
-      const confirmed = await confirmDialog({
-        title: t("panels.file.editor.reloadTitle"),
-        message: t("panels.file.editor.reloadMessage"),
-        confirmLabel: t("panels.file.editor.reload"),
-        destructive: true,
-      });
-      if (confirmed) void model.reload();
-    })();
-  }, [model, snapshot.modified, t]);
-  const handleOverwrite = useCallback(() => void model.overwrite(), [model]);
-  const conflict = fileConflictAlertState({
-    callout: getFileConflictCallout(snapshot),
-    onOverwrite: handleOverwrite,
-    onReload: handleReload,
-    onRetry: onRetryRead,
-    retrying: retryingRead,
-  });
-  const handleVimModeChange = useCallback((nextMode: string | null) => setVimMode(nextMode), []);
-  const renderedPreview = useMemo<ExplorerFile>(
-    () => ({
-      ...preview,
-      content: snapshot.content,
-      size: snapshot.version.status === "ready" ? snapshot.version.size : preview.size,
-      modifiedAt:
-        snapshot.version.status === "ready" ? snapshot.version.modifiedAt : preview.modifiedAt,
-    }),
-    [preview, snapshot.content, snapshot.version],
-  );
-  const showSource = mode !== "preview";
-
-  return (
-    <View style={styles.container} testID="workspace-file-pane">
-      <FilePanelBar
-        size={
-          snapshot.observedVersion.status === "ready" ? snapshot.observedVersion.size : preview.size
-        }
-        lineCount={snapshot.content.split("\n").length}
-        editorStatus={snapshot.status}
-        cursor={showSource ? cursor : undefined}
-        vimMode={showSource ? vimMode : null}
-        conflict={conflict}
-        mode={mode}
-        onModeChange={onModeChange}
-      />
-      {showSource ? (
-        <FileEditorView
-          model={model}
-          filename={filename}
-          location={location}
-          navigationRevision={navigationRevision}
-          vimEnabled={settings.vimKeybindings}
-          theme={visualTheme}
-          onCursorChange={setCursor}
-          onVimModeChange={handleVimModeChange}
-        />
-      ) : (
-        <FilePreviewBody
+        <FilePanelPicker choice={choice} />
+        <FilePanelBar choice={choice} modified={modified} />
+        <MountedFilePanel
+          key={`${panel.id}:${targetKey}`}
           panel={panel}
-          preview={renderedPreview}
-          mode={mode}
-          isLoading={isLoading}
-          isMobile={isMobile}
-          location={location}
-          navigationRevision={navigationRevision}
-          imagePreviewUri={null}
-          workspaceRoot={workspaceRoot}
-          client={client}
-          serverId={serverId}
+          file={handle.file}
+          location={panelLocation}
+          target={panelTarget}
+          onModifiedChange={setModified}
         />
-      )}
+      </View>
+    );
+  }
+  return (
+    <View style={styles.container} testID="workspace-file-pane">
+      <View style={styles.centerState}>{body}</View>
     </View>
   );
 }
 
-function fileConflictAlertState(input: {
-  callout: FileConflictCallout | null;
-  onOverwrite(): void;
-  onReload(): void;
-  onRetry(): void;
-  retrying: boolean;
-}): FileConflictAlertState | undefined {
-  if (!input.callout) return undefined;
-  if (input.callout.kind === "deleted") return { kind: "deleted" };
-  if (input.callout.kind === "checkFailed") {
-    return { kind: "checkFailed", retrying: input.retrying, onRetry: input.onRetry };
-  }
-  return {
-    kind: "changed",
-    canOverwrite: input.callout.canOverwrite,
-    onReload: input.onReload,
-    onOverwrite: input.onOverwrite,
-  };
+/** One panel mount. Its tab reports unsaved changes until the panel unmounts. */
+function MountedFilePanel({
+  panel,
+  file,
+  location,
+  target,
+  onModifiedChange,
+}: {
+  panel: FilePanel;
+  file: PluginFile;
+  location: { lineStart?: number; lineEnd?: number; revision: number };
+  target: { serverId: string; workspaceRoot: string; path: string };
+  onModifiedChange: (modified: boolean) => void;
+}) {
+  const [tab] = useState<PluginFileTab>(() => ({
+    setModified: (modified) => onModifiedChange(modified),
+  }));
+  useEffect(() => () => onModifiedChange(false), [onModifiedChange]);
+  return <FilePanelView panel={panel} file={file} tab={tab} location={location} target={target} />;
 }
 
 const styles = StyleSheet.create((theme) => ({
@@ -654,24 +163,14 @@ const styles = StyleSheet.create((theme) => ({
     gap: theme.spacing[3],
     padding: theme.spacing[4],
   },
-  loadingText: {
-    marginTop: theme.spacing[2],
-    color: theme.colors.foregroundMuted,
-    fontSize: theme.fontSize.base,
-  },
   errorText: {
     color: theme.colors.destructive,
     fontSize: theme.fontSize.base,
     textAlign: "center",
   },
-  emptyText: {
+  mutedText: {
     color: theme.colors.foregroundMuted,
     fontSize: theme.fontSize.base,
     textAlign: "center",
   },
-  binaryMetaText: {
-    marginTop: theme.spacing[2],
-    color: theme.colors.foregroundMuted,
-    fontSize: theme.fontSize.base,
-  },
 }));

packages/app/src/file-pane/preview-lifecycle/hook.ts

@@ -1,23 +0,0 @@
-import { useEffect, useState, useSyncExternalStore } from "react";
-import type { LiveFileSnapshot } from "../live-file/model";
-import {
-  createFilePanePreview,
-  FilePreviewLifecycleModel,
-  type FilePreviewLifecycleSnapshot,
-} from "./model";
-
-/** Bridges the raw-file owner to the preview preparation owner. */
-export function useFilePreview(input: {
-  targetKey: string | null;
-  liveFileSnapshot: LiveFileSnapshot;
-}): FilePreviewLifecycleSnapshot {
-  const [model] = useState(() => new FilePreviewLifecycleModel(createFilePanePreview));
-  const snapshot = useSyncExternalStore(model.subscribe, model.getSnapshot, model.getSnapshot);
-  const { targetKey, liveFileSnapshot } = input;
-
-  useEffect(() => {
-    model.setSource({ targetKey, liveFileSnapshot });
-  }, [liveFileSnapshot, model, targetKey]);
-
-  return snapshot;
-}

packages/app/src/file-pane/preview-lifecycle/model.test.ts

@@ -1,157 +0,0 @@
-import type { FileReadResult } from "@getpaseo/client/internal/daemon-client";
-import type { LiveFileSnapshot } from "../live-file/model";
-import { describe, expect, it } from "vitest";
-import {
-  FilePreviewLifecycleModel,
-  type FilePanePreview,
-  type FilePreviewLifecycleSnapshot,
-} from "./model";
-
-function previewFile(content: string) {
-  return {
-    kind: "text" as const,
-    path: "file.ts",
-    size: 7,
-    encoding: "utf-8" as const,
-    hasBom: false,
-    modifiedAt: "2026-08-20T00:00:00.000Z",
-    content,
-  };
-}
-
-interface Deferred<T> {
-  promise: Promise<T>;
-  resolve(value: T): void;
-  reject(error: Error): void;
-}
-
-function deferred<T>(): Deferred<T> {
-  let resolve!: (value: T) => void;
-  let reject!: (error: Error) => void;
-  const promise = new Promise<T>((onResolve, onReject) => {
-    resolve = onResolve;
-    reject = onReject;
-  });
-  return { promise, resolve, reject };
-}
-
-function file(revision = "revision-1", path = "file.ts"): FileReadResult {
-  return {
-    bytes: new TextEncoder().encode("preview"),
-    mime: "text/plain",
-    size: 7,
-    path,
-    kind: "text",
-    modifiedAt: "2026-08-20T00:00:00.000Z",
-    revision,
-  };
-}
-
-function pending(): LiveFileSnapshot {
-  return { observation: null, read: { status: "pending", requested: false } };
-}
-
-function completed(rawFile: FileReadResult): LiveFileSnapshot {
-  return {
-    observation: {
-      status: "ready",
-      file: rawFile,
-      version: {
-        status: "ready",
-        cwd: "/workspace",
-        path: rawFile.path,
-        size: rawFile.size,
-        modifiedAt: rawFile.modifiedAt,
-        revision: rawFile.revision,
-      },
-    },
-    read: { status: "idle" },
-  };
-}
-
-function source(
-  targetKey: string,
-  snapshot: LiveFileSnapshot,
-): {
-  targetKey: string;
-  liveFileSnapshot: LiveFileSnapshot;
-} {
-  return { targetKey, liveFileSnapshot: snapshot };
-}
-
-describe("FilePreviewLifecycleModel", () => {
-  it("represents pending raw reads, preparation, ready previews, unsupported files, and conversion failures", async () => {
-    const first = deferred<FilePanePreview | null>();
-    const second = deferred<FilePanePreview | null>();
-    const third = deferred<FilePanePreview | null>();
-    const preparations = [first, second, third];
-    const model = new FilePreviewLifecycleModel(() => preparations.shift()!.promise);
-    const preview: FilePanePreview = {
-      file: previewFile("preview"),
-      imageAttachment: null,
-    };
-
-    model.setSource(source("/workspace:file.ts", pending()));
-    expect(model.getSnapshot()).toEqual({ status: "read_pending" });
-
-    model.setSource(source("/workspace:file.ts", completed(file("one"))));
-    expect(model.getSnapshot()).toEqual({ status: "preparing" });
-    first.resolve(preview);
-    await expectSnapshot(model, { status: "ready", preview });
-
-    model.setSource(source("/workspace:file.ts", pending()));
-    expect(model.getSnapshot()).toEqual({ status: "read_pending", preview });
-
-    model.setSource(
-      source("/workspace:file.ts", {
-        observation: {
-          status: "error",
-          cwd: "/workspace",
-          path: "file.ts",
-          error: "Requested path is not a file",
-        },
-        read: { status: "pending", requested: true },
-      }),
-    );
-    expect(model.getSnapshot()).toEqual({ status: "read_pending", preview });
-
-    model.setSource(source("/workspace:file.ts", completed(file("two"))));
-    expect(model.getSnapshot()).toEqual({ status: "preparing", preview });
-    second.resolve(null);
-    await expectSnapshot(model, { status: "unsupported" });
-
-    model.setSource(source("/workspace:file.ts", completed(file("three"))));
-    expect(model.getSnapshot()).toEqual({ status: "preparing" });
-    third.reject(new Error("attachment failed"));
-    await expectSnapshot(model, { status: "error", message: "attachment failed" });
-  });
-
-  it("does not publish a stale conversion after retargeting", async () => {
-    const first = deferred<FilePanePreview | null>();
-    const second = deferred<FilePanePreview | null>();
-    const model = new FilePreviewLifecycleModel((rawFile) =>
-      rawFile.revision === "one" ? first.promise : second.promise,
-    );
-    const nextPreview: FilePanePreview = {
-      file: previewFile("two"),
-      imageAttachment: null,
-    };
-
-    model.setSource(source("/workspace:file.ts", completed(file("one"))));
-    model.setSource(source("/workspace:second.ts", completed(file("two", "second.ts"))));
-    first.resolve({ file: previewFile("one"), imageAttachment: null });
-    await Promise.resolve();
-    expect(model.getSnapshot()).toEqual({ status: "preparing" });
-
-    second.resolve(nextPreview);
-    await expectSnapshot(model, { status: "ready", preview: nextPreview });
-  });
-});
-
-async function expectSnapshot(
-  model: FilePreviewLifecycleModel,
-  expected: FilePreviewLifecycleSnapshot,
-): Promise<void> {
-  await new Promise<void>((resolve) => queueMicrotask(resolve));
-  expect(model.getSnapshot()).toEqual(expected);
-}

packages/app/src/file-pane/preview-lifecycle/model.ts

@@ -1,190 +0,0 @@
-import type { FileReadResult } from "@getpaseo/client/internal/daemon-client";
-import type { AttachmentMetadata } from "@/attachments/types";
-import { persistAttachmentFromBytes } from "@/attachments/service";
-import { createPreviewAttachmentId, getFileNameFromPath } from "@/attachments/utils";
-import { explorerFileFromReadResult } from "@/file-explorer/read-result";
-import type { ExplorerFile } from "@/stores/session-store";
-import type { LiveFileSnapshot } from "../live-file/model";
-
-export interface FilePanePreview {
-  file: ExplorerFile;
-  imageAttachment: AttachmentMetadata | null;
-}
-
-export type FilePreviewLifecycleSnapshot =
-  | { status: "initial" }
-  | { status: "read_pending"; preview?: FilePanePreview }
-  | { status: "preparing"; preview?: FilePanePreview }
-  | { status: "ready"; preview: FilePanePreview }
-  | { status: "error"; message: string; preview?: FilePanePreview }
-  | { status: "unsupported" };
-
-const initialSnapshot: FilePreviewLifecycleSnapshot = { status: "initial" };
-
-/** Converts a completed raw read into the preview resources consumed by FilePane. */
-export async function createFilePanePreview(file: FileReadResult): Promise<FilePanePreview | null> {
-  const explorerFile = explorerFileFromReadResult(file);
-  if (file.kind !== "image") {
-    return { file: explorerFile, imageAttachment: null };
-  }
-
-  const imageAttachment = await persistAttachmentFromBytes({
-    id: createPreviewAttachmentId({
-      mimeType: file.mime,
-      path: file.path,
-      size: file.size,
-      modifiedAt: file.modifiedAt,
-      contentLength: file.bytes.byteLength,
-    }),
-    bytes: file.bytes,
-    mimeType: file.mime,
-    fileName: getFileNameFromPath(file.path),
-  });
-
-  return { file: explorerFile, imageAttachment };
-}
-
-/** Owns conversion after LiveFileModel has produced a raw file snapshot. */
-export class FilePreviewLifecycleModel {
-  private readonly listeners = new Set<() => void>();
-  private snapshot: FilePreviewLifecycleSnapshot = initialSnapshot;
-  private generation = 0;
-  private preparedSourceKey: string | null = null;
-  private targetKey: string | null = null;
-
-  constructor(
-    private readonly prepare: (file: FileReadResult) => Promise<FilePanePreview | null>,
-  ) {}
-
-  subscribe = (listener: () => void): (() => void) => {
-    this.listeners.add(listener);
-    return () => this.listeners.delete(listener);
-  };
-
-  getSnapshot = (): FilePreviewLifecycleSnapshot => this.snapshot;
-
-  setSource(input: { targetKey: string | null; liveFileSnapshot: LiveFileSnapshot }): void {
-    const targetChanged = input.targetKey !== this.targetKey;
-    const retainedPreview = targetChanged ? undefined : filePreviewFromLifecycle(this.snapshot);
-    if (targetChanged) {
-      this.targetKey = input.targetKey;
-      this.preparedSourceKey = null;
-      this.generation += 1;
-    }
-
-    const source = getReadySource(input);
-    if (source) {
-      if (source.key === this.preparedSourceKey) {
-        return;
-      }
-      this.preparedSourceKey = source.key;
-      const generation = ++this.generation;
-      this.setSnapshot({
-        status: "preparing",
-        ...(retainedPreview ? { preview: retainedPreview } : {}),
-      });
-      void this.prepareSource({ file: source.file, generation, retainedPreview });
-      return;
-    }
-
-    const nextSnapshot = getNonReadySnapshot(input.liveFileSnapshot);
-    if (nextSnapshot.status === "initial" && retainedPreview) {
-      return;
-    }
-    const retainedSnapshot = retainedPreview
-      ? { ...nextSnapshot, preview: retainedPreview }
-      : nextSnapshot;
-    if (sameNonReadyState(this.snapshot, retainedSnapshot)) {
-      return;
-    }
-    this.preparedSourceKey = null;
-    this.generation += 1;
-    this.setSnapshot(retainedSnapshot);
-  }
-
-  private setSnapshot(snapshot: FilePreviewLifecycleSnapshot): void {
-    this.snapshot = snapshot;
-    for (const listener of this.listeners) listener();
-  }
-
-  private async prepareSource(input: {
-    file: FileReadResult;
-    generation: number;
-    retainedPreview?: FilePanePreview;
-  }): Promise<void> {
-    try {
-      const preview = await this.prepare(input.file);
-      if (input.generation !== this.generation) return;
-      this.setSnapshot(preview ? { status: "ready", preview } : { status: "unsupported" });
-    } catch (error) {
-      if (input.generation !== this.generation) return;
-      this.setSnapshot({
-        status: "error",
-        message: errorMessage(error),
-        ...(input.retainedPreview ? { preview: input.retainedPreview } : {}),
-      });
-    }
-  }
-}
-
-export function filePreviewFromLifecycle(
-  snapshot: FilePreviewLifecycleSnapshot,
-): FilePanePreview | undefined {
-  return "preview" in snapshot ? snapshot.preview : undefined;
-}
-
-export function resolveFilePreviewLifecycle(snapshot: FilePreviewLifecycleSnapshot): {
-  file: ExplorerFile | null;
-  imageAttachment: AttachmentMetadata | null;
-} {
-  const preview = filePreviewFromLifecycle(snapshot);
-  return preview ?? { file: null, imageAttachment: null };
-}
-
-function getReadySource(input: {
-  targetKey: string | null;
-  liveFileSnapshot: LiveFileSnapshot;
-}): { key: string; file: FileReadResult } | null {
-  const observation = input.liveFileSnapshot.observation;
-  if (!input.targetKey || observation?.status !== "ready") {
-    return null;
-  }
-  const { version } = observation;
-  if (input.targetKey !== `${version.cwd}:${version.path}`) {
-    return null;
-  }
-  return {
-    key: `${input.targetKey}:${version.revision ?? version.modifiedAt}:${version.size}`,
-    file: observation.file,
-  };
-}
-
-function getNonReadySnapshot(snapshot: LiveFileSnapshot): FilePreviewLifecycleSnapshot {
-  if (snapshot.read.status === "error") {
-    return { status: "error", message: snapshot.read.error };
-  }
-  if (snapshot.read.status === "pending") {
-    return { status: "read_pending" };
-  }
-  if (snapshot.observation?.status === "error") {
-    return { status: "error", message: snapshot.observation.error };
-  }
-  if (snapshot.observation?.status === "missing") {
-    return { status: "error", message: "File not found" };
-  }
-  return initialSnapshot;
-}
-
-function sameNonReadyState(
-  current: FilePreviewLifecycleSnapshot,
-  next: FilePreviewLifecycleSnapshot,
-): boolean {
-  if (current.status !== next.status) {
-    return false;
-  }
-  return current.status !== "error" || next.status !== "error" || current.message === next.message;
-}
-
-function errorMessage(error: unknown): string {
-  return error instanceof Error ? error.message : "Failed to prepare preview";
-}

packages/app/src/file-pane/source/view.native.tsx

@@ -1,141 +0,0 @@
-import { useEffect, useMemo, useRef } from "react";
-import { FlatList, Text, View, type ListRenderItem } from "react-native";
-import { StyleSheet } from "react-native-unistyles";
-import { highlightCode, type HighlightToken } from "@getpaseo/highlight";
-import { syntaxTokenStyleFor } from "@/styles/syntax-token-styles";
-import type { WorkspaceFileLocation } from "@/workspace/file-open";
-import type { EditorVisualTheme } from "../editor/extensions.web";
-import { selectSourcePresentation } from "./presentation";
-
-interface FileSourceViewProps {
-  content: string;
-  filename: string;
-  location: WorkspaceFileLocation;
-  navigationRevision: number;
-  size: number;
-  theme: EditorVisualTheme;
-  tooLargeMessage: string;
-}
-
-interface SourceLine {
-  number: number;
-  tokens: HighlightToken[];
-}
-
-export function FileSourceView({
-  content,
-  filename,
-  location,
-  navigationRevision,
-  size,
-  tooLargeMessage,
-}: FileSourceViewProps) {
-  const presentation = selectSourcePresentation({ size, platform: "native" });
-  if (presentation === "unsupported") {
-    return (
-      <View style={styles.unsupported} testID="file-source-too-large">
-        <Text style={styles.unsupportedText}>{tooLargeMessage}</Text>
-      </View>
-    );
-  }
-  return (
-    <VirtualizedSource
-      content={content}
-      filename={filename}
-      location={location}
-      navigationRevision={navigationRevision}
-      presentation={presentation}
-    />
-  );
-}
-
-function VirtualizedSource({
-  content,
-  filename,
-  location,
-  navigationRevision,
-  presentation,
-}: Omit<FileSourceViewProps, "size" | "theme" | "tooLargeMessage"> & {
-  presentation: "highlighted" | "plain";
-}) {
-  const listRef = useRef<FlatList<SourceLine>>(null);
-  const lines = useMemo(() => {
-    if (presentation === "highlighted")
-      return highlightCode(content, filename).map((tokens, index) => ({
-        number: index + 1,
-        tokens,
-      }));
-    return content
-      .split("\n")
-      .map((text, index) => ({ number: index + 1, tokens: [{ text, style: null }] }));
-  }, [content, filename, presentation]);
-  useEffect(() => {
-    if (!location.lineStart) return;
-    listRef.current?.scrollToIndex({
-      index: Math.min(location.lineStart - 1, lines.length - 1),
-      animated: false,
-      viewPosition: 0.5,
-    });
-  }, [lines.length, location.lineStart, navigationRevision]);
-  return (
-    <FlatList
-      ref={listRef}
-      data={lines}
-      keyExtractor={sourceLineKey}
-      initialNumToRender={24}
-      windowSize={9}
-      getItemLayout={sourceLineLayout}
-      renderItem={renderSourceLine}
-    />
-  );
-}
-
-function SourceLineView({ line }: { line: SourceLine }) {
-  return (
-    <View style={styles.line}>
-      <Text style={styles.gutter}>{line.number}</Text>
-      <Text selectable style={styles.text}>
-        {line.tokens.map((token) => (
-          <Text key={`${token.style}:${token.text}`} style={syntaxTokenStyleFor(token.style)}>
-            {token.text}
-          </Text>
-        ))}
-      </Text>
-    </View>
-  );
-}
-
-function sourceLineKey(line: SourceLine): string {
-  return String(line.number);
-}
-
-function sourceLineLayout(_data: ArrayLike<SourceLine> | null | undefined, index: number) {
-  return { length: 20, offset: index * 20, index };
-}
-
-const renderSourceLine: ListRenderItem<SourceLine> = ({ item }) => <SourceLineView line={item} />;
-
-const styles = StyleSheet.create((theme) => ({
-  unsupported: {
-    flex: 1,
-    alignItems: "center",
-    justifyContent: "center",
-    padding: theme.spacing[4],
-  },
-  unsupportedText: { color: theme.colors.foregroundMuted, textAlign: "center" },
-  line: { flexDirection: "row", minHeight: theme.fontSize.code * 1.45 },
-  gutter: {
-    width: 56,
-    paddingRight: theme.spacing[3],
-    textAlign: "right",
-    color: theme.colors.foregroundMuted,
-    fontFamily: theme.fontFamily.mono,
-    fontSize: theme.fontSize.code,
-  },
-  text: {
-    flex: 1,
-    fontFamily: theme.fontFamily.mono,
-    fontSize: theme.fontSize.code,
-    lineHeight: theme.fontSize.code * 1.45,
-  },
-}));

packages/app/src/file-panels/associations.ts

@@ -0,0 +1,34 @@
+import { useCallback } from "react";
+import { useAppSettings } from "@/hooks/use-settings";
+
+export interface FilePanelAssociations {
+  /** Selector key (`ext:md`, `name:Dockerfile`) → panel id, device-wide. */
+  associations: Readonly<Record<string, string>>;
+  /** Writes the association for a selector key, or forgets it with null. */
+  remember(selectorKey: string, panelId: string | null): void;
+}
+
+/** The one reader and writer of the device's file panel associations. */
+export function useFilePanelAssociations(): FilePanelAssociations {
+  const { settings, updateSettings } = useAppSettings();
+  const remember = useCallback(
+    (selectorKey: string, panelId: string | null) => {
+      void updateSettings((current) => ({
+        filePanelAssociations: withAssociation(current.filePanelAssociations, selectorKey, panelId),
+      }));
+    },
+    [updateSettings],
+  );
+  return { associations: settings.filePanelAssociations, remember };
+}
+
+function withAssociation(
+  associations: Readonly<Record<string, string>>,
+  selectorKey: string,
+  panelId: string | null,
+): Record<string, string> {
+  const next = { ...associations };
+  if (panelId === null) delete next[selectorKey];
+  else next[selectorKey] = panelId;
+  return next;
+}

packages/app/src/file-panels/builtin.tsx

@@ -1,92 +1,94 @@
-import type { DaemonClient } from "@getpaseo/client/internal/daemon-client";
+import { useFileText, useFileUrl } from "@getpaseo/plugin/client";
+import { useCallback, useState } from "react";
 import { ScrollView, Text, View } from "react-native";
-import { StyleSheet, withUnistyles } from "react-native-unistyles";
-import { useTranslation } from "react-i18next";
-import { LoadingSpinner } from "@/components/ui/loading-spinner";
+import { StyleSheet } from "react-native-unistyles";
 import { ZoomableImage } from "@/components/zoomable-viewport/image";
-import type { Theme } from "@/styles/theme";
+import { useSessionStore } from "@/stores/session-store";
 import { FileHtmlPreview } from "./html-preview";
+import { FilePanelLoading } from "./loading";
 import { FileMarkdownPreview } from "./markdown-preview";
-import type { builtinFilePanels } from "./catalog";
+import type { BuiltinFilePanelProps } from "./panels";
+import { SourcePanel } from "./source/panel";
+import type { RenderingFilePanel, SourceFilePanel } from "./catalog";
 
-interface FilePanelPreviewProps {
-  content: string;
-  filePath: string;
-  workspaceRoot: string;
-  client: DaemonClient | null;
-  serverId: string;
-  imagePreviewUri: string | null;
-}
-
-function MarkdownPanel(props: FilePanelPreviewProps) {
+/** Shows Loading until the rendered Markdown has laid out once; later re-reads keep the content. */
+function MarkdownPanel({ file, target }: BuiltinFilePanelProps) {
+  const text = useFileText(file);
+  const client = useSessionStore((state) => state.sessions[target.serverId]?.client ?? null);
+  const [rendered, setRendered] = useState(false);
+  const handleLayout = useCallback(() => setRendered(true), []);
+  if (text.status === "loading") return <FilePanelLoading />;
+  if (text.status === "error") return <FilePanelError message={text.error.message} />;
   return (
-    <View style={styles.previewScrollContainer}>
-      <ScrollView style={styles.previewContent} showsVerticalScrollIndicator>
-        <FileMarkdownPreview
-          source={props.content}
-          filePath={props.filePath}
-          workspaceRoot={props.workspaceRoot}
-          client={props.client}
-          serverId={props.serverId}
-        />
+    <View style={styles.container}>
+      <ScrollView style={styles.container} showsVerticalScrollIndicator>
+        <View onLayout={handleLayout}>
+          <FileMarkdownPreview
+            source={text.text}
+            filePath={target.path}
+            workspaceRoot={target.workspaceRoot}
+            client={client}
+            serverId={target.serverId}
+          />
+        </View>
       </ScrollView>
+      {rendered ? null : <FilePanelLoading />}
     </View>
   );
 }
 
-function HtmlPanel({ content }: FilePanelPreviewProps) {
+function HtmlPanel({ file }: BuiltinFilePanelProps) {
+  const text = useFileText(file);
+  if (text.status === "loading") return <FilePanelLoading />;
+  if (text.status === "error") return <FilePanelError message={text.error.message} />;
   return (
-    <View style={styles.previewScrollContainer}>
-      <FileHtmlPreview html={content} testID="file-html-preview" />
+    <View style={styles.container}>
+      <FileHtmlPreview html={text.text} testID="file-html-preview" />
     </View>
   );
 }
 
-const ThemedLoadingSpinner = withUnistyles(LoadingSpinner);
-const foregroundMutedColorMapping = (theme: Theme) => ({ color: theme.colors.foregroundMuted });
+function ImagePanel({ file }: BuiltinFilePanelProps) {
+  const url = useFileUrl(file);
+  if (url.status === "loading") return <FilePanelLoading />;
+  if (url.status === "error") return <FilePanelError message={url.error.message} />;
+  return <ZoomableImage uri={url.url} testID="image-file-preview" />;
+}
 
-function ImagePanel({ imagePreviewUri }: FilePanelPreviewProps) {
-  const { t } = useTranslation();
-  if (!imagePreviewUri) {
-    return (
-      <View style={styles.centerState}>
-        <ThemedLoadingSpinner size="small" uniProps={foregroundMutedColorMapping} />
-        <Text style={styles.loadingText}>{t("panels.file.loading")}</Text>
-      </View>
-    );
-  }
-  return <ZoomableImage uri={imagePreviewUri} testID="image-file-preview" />;
+function FilePanelError({ message }: { message: string }) {
+  return (
+    <View style={styles.centerState}>
+      <Text style={styles.errorText}>{message}</Text>
+    </View>
+  );
 }
 
 const components = {
   "builtin:markdown": MarkdownPanel,
   "builtin:html": HtmlPanel,
   "builtin:image": ImagePanel,
+  "builtin:source": SourcePanel,
 };
 
-export function FilePanelPreview({
+export function BuiltinFilePanelView({
   panel,
   ...props
-}: FilePanelPreviewProps & {
-  panel: (typeof builtinFilePanels)[number];
-}) {
+}: BuiltinFilePanelProps & { panel: RenderingFilePanel | SourceFilePanel }) {
   const Component = components[panel.id];
   return <Component {...props} />;
 }
 
 const styles = StyleSheet.create((theme) => ({
-  previewScrollContainer: { flex: 1, minHeight: 0 },
-  previewContent: { flex: 1, minHeight: 0 },
+  container: { flex: 1, minHeight: 0 },
   centerState: {
     flex: 1,
     alignItems: "center",
     justifyContent: "center",
-    gap: theme.spacing[3],
     padding: theme.spacing[4],
   },
-  loadingText: {
-    marginTop: theme.spacing[2],
-    color: theme.colors.foregroundMuted,
+  errorText: {
+    color: theme.colors.destructive,
     fontSize: theme.fontSize.base,
+    textAlign: "center",
   },
 }));

packages/app/src/file-panels/catalog.test.ts

@@ -1,86 +1,74 @@
 import { describe, expect, it } from "vitest";
-import { builtinFilePanels, isRenderedMarkdownFile } from "./catalog";
-import { resolveFilePanel } from "./resolve";
+import { filePanelCatalog } from "./catalog";
+import { resolveFilePanel, type FilePanelCandidate, type FilePanelFile } from "./resolve";
 
-function filePreviewRenderKind(path: string) {
-  const { panel } = resolveFilePanel({
-    file: { path, kind: "text", size: 100, hasBytes: false },
-    candidates: builtinFilePanels,
-    associations: {},
-  });
-  return panel ? panel.id.slice("builtin:".length) : null;
+const builtins = filePanelCatalog([]);
+
+const richMarkdown: FilePanelCandidate = {
+  id: "plugin:notes/rich",
+  builtin: false,
+  files: { extensions: ["md"] },
+};
+
+function textFile(path: string): FilePanelFile {
+  return { path, kind: "text" };
 }
 
-describe("isRenderedMarkdownFile", () => {
-  it("detects .md files", () => {
-    expect(isRenderedMarkdownFile("README.md")).toBe(true);
-    expect(isRenderedMarkdownFile("docs/guide.MD")).toBe(true);
-  });
+function candidateIds(file: FilePanelFile, candidates: readonly FilePanelCandidate[] = builtins) {
+  return resolveFilePanel({ file, candidates, associations: {} }).candidates.map(
+    (candidate) => candidate.id,
+  );
+}
 
-  it("detects .markdown files", () => {
-    expect(isRenderedMarkdownFile("notes.markdown")).toBe(true);
-    expect(isRenderedMarkdownFile("docs/CHANGELOG.MARKDOWN")).toBe(true);
-  });
-
-  it("does not treat .mdx files as rendered markdown", () => {
-    expect(isRenderedMarkdownFile("page.mdx")).toBe(false);
-  });
-
-  it("does not treat other text files as rendered markdown", () => {
-    expect(isRenderedMarkdownFile("src/index.ts")).toBe(false);
-    expect(isRenderedMarkdownFile("README.md.txt")).toBe(false);
-    expect(isRenderedMarkdownFile("plan.html")).toBe(false);
-  });
-});
-
-describe("filePreviewRenderKind", () => {
-  it("maps each renderable extension to its kind", () => {
-    expect(filePreviewRenderKind("README.md")).toBe("markdown");
-    expect(filePreviewRenderKind("notes.markdown")).toBe("markdown");
-    expect(filePreviewRenderKind("plan.html")).toBe("html");
-    expect(filePreviewRenderKind("docs/PLAN.HTML")).toBe("html");
-    expect(filePreviewRenderKind("plan.htm")).toBe("html");
-  });
-
-  it("returns null for files without a rendered preview", () => {
-    expect(filePreviewRenderKind("src/index.ts")).toBe(null);
-    expect(filePreviewRenderKind("page.mdx")).toBe(null);
-    expect(filePreviewRenderKind("index.html.erb")).toBe(null);
-  });
-});
+function panelId(file: FilePanelFile, candidates: readonly FilePanelCandidate[] = builtins) {
+  return resolveFilePanel({ file, candidates, associations: {} }).panel?.id ?? null;
+}
 
 describe("built-in file panels", () => {
+  it("opens each rendered extension with its panel and Source after it", () => {
+    expect(candidateIds(textFile("README.md"))).toEqual(["builtin:markdown", "builtin:source"]);
+    expect(panelId(textFile("notes.markdown"))).toBe("builtin:markdown");
+    expect(panelId(textFile("plan.html"))).toBe("builtin:html");
+    expect(panelId(textFile("docs/PLAN.HTML"))).toBe("builtin:html");
+    expect(panelId(textFile("plan.htm"))).toBe("builtin:html");
+  });
+
+  it("opens every other text file with Source, whatever its name", () => {
+    for (const path of ["src/index.ts", "page.mdx", "index.html.erb", "Dockerfile", "LICENSE"]) {
+      expect(candidateIds(textFile(path))).toEqual(["builtin:source"]);
+    }
+  });
+
+  it("puts plugin panels after the rendering built-ins and before Source", () => {
+    expect(candidateIds(textFile("README.md"), filePanelCatalog([richMarkdown]))).toEqual([
+      "builtin:markdown",
+      richMarkdown.id,
+      "builtin:source",
+    ]);
+    const onlyPlugin = filePanelCatalog([{ ...richMarkdown, files: { extensions: ["txt"] } }]);
+    expect(panelId(textFile("notes.txt"), onlyPlugin)).toBe(richMarkdown.id);
+  });
+
+  it("has no Source for files that are not text", () => {
+    expect(candidateIds({ path: "archive.zip", kind: "binary" })).toEqual([]);
+  });
+
   it.each(["png", "jpg", "jpeg", "gif", "webp", "svg"])(
     "registers the image extension %s",
     (extension) => {
       const resolution = resolveFilePanel({
-        file: {
-          path: `/capture.${extension.toUpperCase()}`,
-          kind: "image",
-          size: 512,
-          hasBytes: true,
-        },
-        candidates: builtinFilePanels,
+        file: { path: `/capture.${extension.toUpperCase()}`, kind: "image" },
+        candidates: builtins,
         associations: { [`ext:${extension}`]: "builtin:markdown" },
       });
       expect(resolution.panel?.id).toBe("builtin:image");
       expect(
         resolveFilePanel({
-          file: { path: "capture.png", kind: "binary", size: 512, hasBytes: false },
-          candidates: builtinFilePanels,
+          file: { path: "capture.png", kind: "binary" },
+          candidates: builtins,
           associations: {},
         }).panel,
       ).toBeNull();
     },
   );
-
-  it("does not impose a new preview size limit on built-in text panels", () => {
-    expect(
-      resolveFilePanel({
-        file: { path: "notes.md", kind: "text", size: 11 * 1024 * 1024, hasBytes: false },
-        candidates: builtinFilePanels,
-        associations: {},
-      }).panel?.id,
-    ).toBe("builtin:markdown");
-  });
 });

packages/app/src/file-panels/catalog.ts

@@ -1,28 +1,43 @@
-import { filePanelExtension, type FilePanelCandidate } from "./resolve";
+import type { FilePanelCandidate } from "./resolve";
 
-const markdownPanel = {
-  id: "builtin:markdown",
-  files: { extensions: ["md", "markdown"] },
-  document: "text",
-  maxBytes: Infinity,
-} as const satisfies FilePanelCandidate;
-
-export const builtinFilePanels = [
-  markdownPanel,
+const renderingPanels = [
+  {
+    id: "builtin:markdown",
+    builtin: true,
+    files: { extensions: ["md", "markdown"] },
+    fileKind: "text",
+  },
   {
     id: "builtin:html",
+    builtin: true,
     files: { extensions: ["html", "htm"] },
-    document: "text",
-    maxBytes: Infinity,
+    fileKind: "text",
   },
   {
     id: "builtin:image",
+    builtin: true,
     files: { extensions: ["png", "jpg", "jpeg", "gif", "webp", "svg"] },
-    document: "bytes",
-    maxBytes: Infinity,
+    fileKind: "image",
   },
 ] as const satisfies readonly FilePanelCandidate[];
 
-export function isRenderedMarkdownFile(path: string): boolean {
-  return markdownPanel.files.extensions.some((extension) => extension === filePanelExtension(path));
+/** Paseo's editor. Every text file has it, so a text file always opens with some panel. */
+export const sourceFilePanel = {
+  id: "builtin:source",
+  builtin: true,
+  files: "all",
+  fileKind: "text",
+} as const satisfies FilePanelCandidate;
+
+export type RenderingFilePanel = (typeof renderingPanels)[number];
+export type SourceFilePanel = typeof sourceFilePanel;
+
+/**
+ * Every panel a host offers, in resolver order: the built-ins that render a file, then plugin
+ * panels, then Source. Source is last so it is the default only when nothing else claims the file.
+ */
+export function filePanelCatalog<Plugin extends FilePanelCandidate>(
+  pluginPanels: readonly Plugin[],
+): readonly (RenderingFilePanel | Plugin | SourceFilePanel)[] {
+  return [...renderingPanels, ...pluginPanels, sourceFilePanel];
 }

packages/app/src/file-panels/choice/hook.ts

@@ -0,0 +1,88 @@
+import { useCallback, useEffect, useMemo, useState, useSyncExternalStore } from "react";
+import { usePaneContext } from "@/panels/pane-context";
+import type { PanelInstanceIdentity } from "@/panels/panel-instance-attributes";
+import { useFilePanelAssociations } from "../associations";
+import { sourceFilePanel } from "../catalog";
+import { useFilePanels, type FilePanel } from "../panels";
+import { resolveFilePanel, type FilePanelFileKind } from "../resolve";
+import { chosenPanelFor, FilePanelChoiceModel, type FilePanelChoiceSnapshot } from "./model";
+import { getFilePanelChoice, registerFilePanelChoice, subscribeFilePanelChoices } from "./registry";
+
+export type FilePanelChoice = FilePanelChoiceModel<FilePanel>;
+
+/**
+ * The file tab's panel: resolves it from the catalog, the device associations and this tab's
+ * choice, and owns the picker and "Open with…" for it.
+ */
+export function useFilePanelChoice(input: {
+  serverId: string;
+  targetKey: string | null;
+  path: string;
+  /** The kind the file's stat reports, or null before the stat. */
+  fileKind: FilePanelFileKind | null;
+  /** The tab is on screen. */
+  presentable: boolean;
+  /** Identifies the tab's latest request to show a line, or null when it targets no line. */
+  lineNavigation: number | null;
+}): { panel: FilePanel | null; choice: FilePanelChoice } {
+  const { targetKey, path, fileKind, presentable, lineNavigation } = input;
+  const { serverId, workspaceId, tabId } = usePaneContext();
+  const candidates = useFilePanels(input.serverId);
+  const { associations, remember } = useFilePanelAssociations();
+  const [choice] = useState(
+    () => new FilePanelChoiceModel<FilePanel>({ remember, linePanelId: sourceFilePanel.id }),
+  );
+  // From the subscribed snapshot: React Compiler caches reads off the stable model object.
+  const chosenPanelId = chosenPanelFor(useFilePanelChoiceSnapshot(choice), targetKey);
+  const resolution = useMemo(
+    () =>
+      fileKind
+        ? resolveFilePanel({
+            file: { path, kind: fileKind },
+            candidates,
+            associations,
+            choice: chosenPanelId,
+          })
+        : null,
+    [associations, candidates, chosenPanelId, fileKind, path],
+  );
+
+  useEffect(() => {
+    choice.observe({ targetKey, resolution, presentable, lineNavigation });
+  }, [choice, lineNavigation, presentable, resolution, targetKey]);
+  useEffect(
+    () => registerFilePanelChoice({ serverId, workspaceId, tabId }, choice),
+    [choice, serverId, tabId, workspaceId],
+  );
+
+  return { panel: resolution?.panel ?? null, choice };
+}
+
+const NO_CHOICE_SNAPSHOT: FilePanelChoiceSnapshot<FilePanel> = {
+  targetKey: null,
+  chosenPanelId: null,
+  picker: null,
+  openWith: null,
+};
+const subscribeNothing = () => () => {};
+const getNoChoiceSnapshot = () => NO_CHOICE_SNAPSHOT;
+
+/** The choice of an open file tab, looked up by the tab's identity, for chrome outside its pane. */
+export function useTabFilePanelChoice(identity: PanelInstanceIdentity): FilePanelChoice | null {
+  const { serverId, workspaceId, tabId } = identity;
+  const getSnapshot = useCallback(
+    () => getFilePanelChoice({ serverId, workspaceId, tabId }),
+    [serverId, tabId, workspaceId],
+  );
+  return useSyncExternalStore(subscribeFilePanelChoices, getSnapshot, getSnapshot);
+}
+
+export function useFilePanelChoiceSnapshot(
+  choice: FilePanelChoice | null,
+): FilePanelChoiceSnapshot<FilePanel> {
+  return useSyncExternalStore(
+    choice?.subscribe ?? subscribeNothing,
+    choice?.getSnapshot ?? getNoChoiceSnapshot,
+    choice?.getSnapshot ?? getNoChoiceSnapshot,
+  );
+}

packages/app/src/file-panels/choice/model.test.ts

@@ -0,0 +1,203 @@
+import { describe, expect, it } from "vitest";
+import { filePanelCatalog, sourceFilePanel } from "../catalog";
+import { resolveFilePanel, type FilePanelCandidate } from "../resolve";
+import { chosenPanelFor, FilePanelChoiceModel } from "./model";
+
+const rich: FilePanelCandidate = {
+  id: "plugin:notes/rich",
+  builtin: false,
+  files: { extensions: ["md", "markdown"] },
+};
+const markdown = "builtin:markdown";
+const source = sourceFilePanel.id;
+
+/** A file tab: resolves against the shared associations and feeds the result to its model. */
+function openTab(
+  associations: Record<string, string>,
+  candidates: FilePanelCandidate[] = [...filePanelCatalog([rich])],
+  options: { presentable?: boolean; path?: string; lineNavigation?: number | null } = {},
+) {
+  const model = new FilePanelChoiceModel<FilePanelCandidate>({
+    remember(selectorKey, panelId) {
+      if (panelId === null) delete associations[selectorKey];
+      else associations[selectorKey] = panelId;
+    },
+    linePanelId: source,
+  });
+  let targetKey = `/repo:${options.path ?? "notes.md"}`;
+  let presentable = options.presentable ?? true;
+  let lineNavigation = options.lineNavigation ?? null;
+  const resolve = () =>
+    resolveFilePanel({
+      file: { path: targetKey.split(":")[1]!, kind: "text" },
+      candidates,
+      associations,
+      choice: chosenPanelFor(model.getSnapshot(), targetKey),
+    });
+  // Like the hook: observe, then render what the model's choice resolves to.
+  const render = () => {
+    model.observe({ targetKey, resolution: resolve(), presentable, lineNavigation });
+    return resolve().panel?.id ?? null;
+  };
+  render();
+  return {
+    model,
+    render,
+    panel: () => render(),
+    picker: () => model.getSnapshot().picker,
+    retarget(path: string) {
+      targetKey = `/repo:${path}`;
+      return render();
+    },
+    setPresentable(next: boolean) {
+      presentable = next;
+      return render();
+    },
+    navigateToLine(revision: number) {
+      lineNavigation = revision;
+      return render();
+    },
+  };
+}
+
+describe("FilePanelChoiceModel", () => {
+  it("asks once per tab open over the first candidate, and dismissing keeps it", () => {
+    const associations = {};
+    const tab = openTab(associations);
+    expect(tab.panel()).toBe(markdown);
+    expect(tab.picker()).toMatchObject({
+      selectorKey: "ext:md",
+      selectedPanelId: markdown,
+      remember: false,
+    });
+    expect(tab.picker()?.candidates.map((candidate) => candidate.id)).toEqual([
+      markdown,
+      rich.id,
+      source,
+    ]);
+    tab.model.dismissPicker();
+    expect(tab.picker()).toBeNull();
+    expect(tab.panel()).toBe(markdown);
+    expect(tab.picker()).toBeNull();
+    expect(associations).toEqual({});
+
+    expect(openTab(associations).picker()).not.toBeNull();
+  });
+
+  it("never asks between built-in panels, and switches between them", () => {
+    const tab = openTab({}, [...filePanelCatalog([])]);
+    expect(tab.panel()).toBe(markdown);
+    expect(tab.picker()).toBeNull();
+    expect(tab.model.getSnapshot().openWith?.candidates.map((candidate) => candidate.id)).toEqual([
+      markdown,
+      source,
+    ]);
+    tab.model.openWith(source);
+    expect(tab.panel()).toBe(source);
+    expect(tab.picker()).toBeNull();
+  });
+
+  it("opens a file only Source claims with Source and nothing to choose", () => {
+    const tab = openTab({}, [...filePanelCatalog([rich])], { path: "index.ts" });
+    expect(tab.panel()).toBe(source);
+    expect(tab.picker()).toBeNull();
+    expect(tab.model.getSnapshot().openWith).toBeNull();
+  });
+
+  it("remembers the choice when Don't ask me again is checked", () => {
+    const associations: Record<string, string> = {};
+    const tab = openTab(associations);
+    tab.model.selectInPicker(rich.id);
+    tab.model.setRemember(true);
+    tab.model.confirmPicker();
+    expect(tab.panel()).toBe(rich.id);
+    expect(associations).toEqual({ "ext:md": rich.id });
+
+    const next = openTab(associations);
+    expect(next.panel()).toBe(rich.id);
+    expect(next.picker()).toBeNull();
+  });
+
+  it("uses an unremembered choice for this tab only and asks again on the next open", () => {
+    const associations = {};
+    const tab = openTab(associations);
+    tab.model.selectInPicker(rich.id);
+    tab.model.confirmPicker();
+    expect(tab.panel()).toBe(rich.id);
+    expect(associations).toEqual({});
+
+    const next = openTab(associations);
+    expect(next.panel()).toBe(markdown);
+    expect(next.picker()).not.toBeNull();
+  });
+
+  it("does not ask with an association or while the tab is in the background", () => {
+    expect(openTab({ "ext:md": rich.id }).picker()).toBeNull();
+    expect(openTab({ "ext:md": source }).panel()).toBe(source);
+
+    const background = openTab({}, undefined, { presentable: false });
+    expect(background.picker()).toBeNull();
+    background.setPresentable(true);
+    expect(background.picker()).not.toBeNull();
+  });
+
+  it("opens Source for a line target without asking, and again on each new one", () => {
+    const tab = openTab({}, undefined, { lineNavigation: 1 });
+    expect(tab.panel()).toBe(source);
+    expect(tab.picker()).toBeNull();
+
+    tab.model.openWith(rich.id);
+    expect(tab.panel()).toBe(rich.id);
+    expect(tab.navigateToLine(1)).toBe(rich.id);
+    expect(tab.navigateToLine(2)).toBe(source);
+  });
+
+  it("opens Source for the same line target in a retargeted tab", () => {
+    const tab = openTab({}, undefined, { lineNavigation: 1 });
+    tab.model.openWith(markdown);
+    expect(tab.retarget("other.md")).toBe(source);
+  });
+
+  it("starts a new open when the tab is retargeted", () => {
+    const tab = openTab({});
+    tab.model.selectInPicker(rich.id);
+    tab.model.confirmPicker();
+    expect(tab.retarget("other.md")).toBe(markdown);
+    expect(tab.picker()).not.toBeNull();
+  });
+
+  it("switches with Open with and toggles Always use without moving the tab", () => {
+    const associations: Record<string, string> = {};
+    const tab = openTab(associations);
+    tab.model.dismissPicker();
+    expect(tab.model.getSnapshot().openWith).toMatchObject({
+      activePanelId: markdown,
+      remembered: false,
+    });
+
+    tab.model.openWith(rich.id);
+    expect(tab.panel()).toBe(rich.id);
+    tab.model.toggleAlwaysUse();
+    expect(associations).toEqual({ "ext:md": rich.id });
+    tab.render();
+    expect(tab.model.getSnapshot().openWith?.remembered).toBe(true);
+
+    tab.model.openWith(markdown);
+    expect(tab.panel()).toBe(markdown);
+    expect(tab.model.getSnapshot().openWith?.remembered).toBe(false);
+    tab.model.openWith(rich.id);
+    tab.render();
+    tab.model.toggleAlwaysUse();
+    expect(associations).toEqual({});
+    expect(tab.panel()).toBe(rich.id);
+  });
+
+  it("asks when a plugin panel arrives after the file first rendered", () => {
+    const candidates: FilePanelCandidate[] = [...filePanelCatalog([])];
+    const tab = openTab({}, candidates);
+    expect(tab.picker()).toBeNull();
+    candidates.splice(1, 0, rich);
+    tab.render();
+    expect(tab.picker()).not.toBeNull();
+  });
+});