fix(app): keep composer layout stable across chat and workspace screens (#4973)

* fix(app): dock the New workspace composer like a chat on phones

Only the composer is bounded by the viewport; the setup fields sit above it in a
bottom-anchored stack that moves up as the draft grows. The keyboard reservation
is retained on every screen, so the composer keeps one height across keyboard
transitions. Removes the per-screen reserve policy.

* fix(app): share composer docking across mobile hosts

Extract chat's retained capacity and platform keyboard motion so chat,
workspace drafts, and New workspace share one sizing and dismissal boundary.
Keep the native drivers and settled portal reconciliation unchanged.

* fix(app): preserve overlays in centered composer docks

Honor the optional overlay child in both layouts so changing dock placement does not silently discard part of its content.

* test(app): resolve keyboard controller through its web entry

The shared keyboard entry point makes stream tests load the provider. Keep its real ESM dependencies inside the Vitest resolver so CommonJS does not bypass the React Native web alias and parse native Flow sources.

* fix(app): keep native chat scrolling responsive

Place keyboard dismissal behind scrollable content so an idle Android Fabric JS responder cannot intercept native drags. Keep decorative form padding transparent to iOS hit testing and exercise idle native scrolling after submission from every composer host.

docs/mobile-testing.md

@@ -47,13 +47,33 @@ focused input identity and IME hide/show events. It saves screenshots and logs u
 `.dev/agent-device-artifacts/terminal-keyboard-android`. Set `PASEO_TERMINAL_KEYBOARD_APP_ID=sh.paseo`
 to test an installed production build. It never submits a chat message.
 
-`npm run test:e2e:composer-keyboard:android` covers composer growth in chat and
-New workspace, plus keyboard and control interactions. Configure its daemon,
+`npm run test:e2e:composer-keyboard:android` preserves the chat control and
+keyboard regression flow, then runs the same growth, retained-height, bounds, and
+hold-to-delete and background-tap dismissal scenario on chat, a workspace draft
+tab, and New workspace. It checks empty-content taps and header taps at the cap
+without changing the input height. Each
+host also opens command/file autocomplete, the model selector, the attachment
+menu, and the forge picker from both keyboard states. It then submits a long
+fixture from each host and checks native stream displacement twice: after the
+response settles, and after returning to the bottom and letting the scrollbar
+fade. The image comparison excludes the scrollbar; keyboard dismissal alone
+does not prove that native scrolling receives touches.
+Artifacts are grouped by host under
+`.dev/agent-device-artifacts/composer-keyboard-android`. Configure its daemon,
 Metro, and device through the `PASEO_COMPOSER_KEYBOARD_*` variables in
 `packages/app/e2e/mobile/composer-keyboard/android.sh`. Use a software keyboard;
 the headless input helper cannot verify the
 [visible composer constraints](floating-panels.md#gotcha-3--keyboard-layout-and-portal-anchors).
 
+On a Play-image emulator, disable Gmail and Calendar first. Their welcome
+screens launch on their own, take input focus, and the run fails with
+`IME did not become visible` while the app still looks focused:
+
+```bash
+adb shell pm disable-user --user 0 com.google.android.gm
+adb shell pm disable-user --user 0 com.google.android.calendar
+```
+
 When replay diverges, read its ranked selector suggestions. Edit the script deliberately and rerun it from the beginning. `--update` is retained for compatibility but no longer rewrites scripts.
 
 ## Maestro compatibility