…e detection

…back

…ew one per keystroke

- Simplify refocus effect to always restore focus after layout transition
  (layout only changes due to user typing, so they always have focus)
- Remove unnecessary value dependency from refocus effect
- Add canvas ref cleanup on unmount for garbage collection
- Improve E2E test efficiency by using fill() instead of loop-based backspace
- Add negative assertion to verify short text stays in inline mode

Track previous isStacked value to detect actual layout transitions
instead of just checking mount state. This prevents the textarea from
stealing focus when the page initially loads.

- Use flexbox align-items: center for proper vertical alignment
- Reduce container padding to md (12px) for 58px total height
- Reduce textarea padding to twoXS (4px)
- Add alignItems: center to inline textarea wrapper
- Fix auto-focus on page load by tracking actual layout transitions

Instead of rendering UITextArea in different DOM positions (which causes
remount and focus loss), keep it at a fixed position and use CSS flex
properties (order, width, flex-wrap) to visually move it above buttons
when in stacked mode. This eliminates the need for manual focus/cursor
restoration after layout transitions.

- Fix textarea alignment after audio recording/submission by using
  height: auto when not in extended mode
- Re-measure textarea width when recording ends to ensure stacked
  layout detection works correctly after audio submission
- Add e2e tests for layout alignment and stacking after audio events

- Move waveform inline with cancel/approve buttons during recording
- Adjust waveform height to match button size for consistent layout
- Add type=button to file upload button to fix click handling

Use useLayoutEffect instead of setTimeout to measure textarea dimensions.
This provides deterministic timing as useLayoutEffect runs synchronously
after DOM mutations, guaranteeing the ref exists when we measure.