[Bug]: iPhone dictation into the collapsed composer clips a multi-line transcript to one line #16462

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/mobile (iOS)

Steps to reproduce

1. Open an existing thread on iPhone with the keyboard down, so the composer is the collapsed one-line pill.
2. Tap the composer's mic button and dictate a few sentences.
3. Stop dictation and let the transcript land.

Expected behavior

The composer grows to show the whole transcript so it can be reviewed before sending, as docs/user/composer.md describes ("ready for you to review and edit before sending").

Actual behavior

The composer stays one line tall and the transcript is clipped. The rest can't even be scrolled. The full text only appears after tapping the composer, which focuses it and brings up the keyboard.

Impact

You can't review a dictated prompt without opening the keyboard. That defeats the point of dictating with the keyboard down, and makes it easy to send a transcript you haven't read.

Version or commit

iOS app 2.0.0 (109). Source checked on main at 68e50db.

Root cause

• The composer expands only when focused: const isExpanded = isFocused || settingsSheetPresentation.keepsComposerExpanded; (apps/mobile/src/features/threads/ThreadComposer.tsx:525).
• When collapsed, the editor is fixed at height: 36 with scrollEnabled={false} (ThreadComposer.tsx:1001, :1013-1015).
• Dictation commits the transcript to the draft store without focusing the editor (useVoiceInputController.ts:51-56 → setComposerDraftText), so nothing makes the composer grow.
• The native iOS editor does emit onComposerContentSizeChange after programmatic value changes (T3ComposerEditorView.swift:857), but nothing in apps/mobile/src listens for it.

Suggested fix

When a transcript lands in an unfocused composer, open it to its expanded reading height without focusing the editor. Tapping the text focuses it; tapping the conversation collapses it again. Open PR #15236 implements exactly this in ThreadComposer.tsx and ThreadDetailScreen.tsx. It's a V2 rebuild of #12917 but now conflicts with main. A broader alternative is to drive the collapsed height from content size (the closed #14451 took that route).

Workaround

Tap into the composer after dictating to see the full text.