The Flutter client had no audio_session integration, so it didn't pause
for phone calls / other media, didn't duck for navigation prompts, and
kept blasting the phone speaker when earbuds were unplugged.
Add audio_session ^0.2.3 and configure AudioSessionConfiguration.music()
in MinstrelAudioHandler (best-effort, fully try-caught):
- becomingNoisy -> pause (no speaker blast on unplug/BT drop)
- interruption begin: duck -> lower volume; pause/unknown -> pause,
remembering whether we were actively playing
- interruption end: duck -> restore volume; pause -> resume only if we
paused it and the session isn't torn down (guards the idle-teardown
-during-long-call edge; re-init is resume-last-session territory);
unknown -> no auto-resume
pubspec.lock regenerated by build/CI.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>