Pre-commit analyze gate requires zero issues; this pre-existing
warning was blocking the schema commit.
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
Timer stops playback (pause) after 5/10/15/30/60 min. Wall-clock
deadline is self-correcting against OS throttling; 1Hz tick drives
the countdown UI. Cancelled in stop() so no timer resurrects a paused
player after teardown.
- sleep_timer.dart: isolated time logic, injectable clock for testing
- audio_handler.dart: sleepTimer field + cancel() in stop()
- now_playing_screen.dart: AppBar button + bottom sheet
- 10 unit tests via mocked clock
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
