fix(app): keep chat keyboard scrolling after closing Find

Closing Find focused its non-scrolling wrapper, leaving Page Up and Page Down unable to move the feed. Return focus through the viewport handle while preserving the reading position.

packages/app/e2e/browser/chat-find.spec.ts

@@ -5,6 +5,7 @@ import {
   seedMockAgentWorkspace,
   type MockAgentWorkspace,
 } from "../support/helpers/mock-agent";
+import { waitForTimelineGeometryToSettle } from "../support/helpers/timeline-pagination";
 import { installDaemonWebSocketGate } from "../support/helpers/daemon-websocket-gate";
 import {
   expectReconnectingToastGone,
@@ -124,6 +125,49 @@ async function closeFind(page: Page) {
     .toEqual([]);
 }
 
+async function expectChatKeyboardScroll(page: Page, key: "PageUp" | "PageDown") {
+  // The scrolling surface has no accessible name; use its existing test id.
+  const viewport = page.getByTestId("agent-chat-scroll");
+  await waitForTimelineGeometryToSettle(page);
+  const before = await viewport.evaluate((element) => element.scrollTop);
+  await page.keyboard.press(key);
+  const direction = key === "PageUp" ? -1 : 1;
+  await expect
+    .poll(
+      async () => direction * ((await viewport.evaluate((element) => element.scrollTop)) - before),
+    )
+    .toBeGreaterThan(100);
+}
+
+test("keeps keyboard scrolling the chat after closing Find", async ({ page }, testInfo) => {
+  const agent = await seedMockAgentWorkspace({
+    repoPrefix: "chat-find-scroll-focus-",
+    title: "Chat Find keyboard scrolling",
+    initialPrompt: "Render the response",
+    featureValues: { mockAssistantResponse: TALL_RESPONSE },
+  });
+  try {
+    await agent.client.waitForFinish(agent.agentId, 15_000);
+    await openAgentRoute(page, agent);
+    await expect(page.getByTestId("assistant-message").first()).toBeVisible();
+    await searchChat(page, "Closing paragraph");
+    await expectHighlight(page, "Closing paragraph");
+    await waitForTimelineGeometryToSettle(page);
+    await closeFind(page);
+    await expectChatKeyboardScroll(page, "PageUp");
+    await page.screenshot({ path: testInfo.outputPath("chat-after-find-page-up.png") });
+    await expectChatKeyboardScroll(page, "PageDown");
+    await searchChat(page, "Closing paragraph");
+    await expectHighlight(page, "Closing paragraph");
+    await waitForTimelineGeometryToSettle(page);
+    await page.getByRole("button", { name: "Close Find", exact: true }).click();
+    await expect(query(page)).toHaveCount(0);
+    await expectChatKeyboardScroll(page, "PageUp");
+  } finally {
+    await agent.cleanup();
+  }
+});
+
 test("loads older history through prompt navigation and finds repeated rendered Markdown", async ({
   page,
 }, testInfo) => {

packages/app/src/agent-stream/chat-find/index.web.tsx

@@ -118,8 +118,8 @@ export function ChatFind({
   }, [active, isInteractive, model]);
   const close = useCallback(() => {
     model.close();
-    root.current?.focus({ preventScroll: true });
-  }, [model]);
+    viewportRef.current?.focus?.();
+  }, [model, viewportRef]);
   let status = "";
   if (state.phase === "searching") status = t("paneFind.searching");
   else if (state.phase === "loading") status = t("paneFind.loading");

packages/app/src/agent-stream/strategy-web.tsx

@@ -1162,6 +1162,7 @@ function WebStreamViewport(props: StreamRenderInput & { isMobileBreakpoint: bool
 
   useEffect(() => {
     const handle: StreamViewportHandle = {
+      focus: () => scrollContainerRef.current?.focus({ preventScroll: true }),
       scrollToBottom: () => {
         setFollowOutput(true);
         cancelPendingStickToBottom();

packages/app/src/agent-stream/strategy.ts

@@ -51,6 +51,8 @@ export interface ScrollToMessageOccurrence {
 }
 
 export interface StreamViewportHandle {
+  /** Give keyboard navigation back to the scrolling surface on web. */
+  focus?: () => void;
   scrollToBottom: (reason?: BottomAnchorLocalRequest["reason"]) => void;
   prepareForViewportChange: () => void;
   scrollToMessage?: (messageId: string, occurrence?: ScrollToMessageOccurrence) => void;