W-02: Renamed layout/AmbientBackground → AppAmbientBackground to avoid
naming collision with auth/AmbientBackground (IDE auto-import confusion).
S-01: Added visibilitychange listener to re-sync clock after tab
sleep/resume. Previously the interval would drift after laptop sleep
or long tab backgrounding.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>