Download albums/playlists to private device storage (Room + WorkManager,
HttpURLConnection streaming). New Offline tab lists groups with progress;
tapping a group opens a detail screen (cover-art rows, play/shuffle, per-song
delete from device). Downloaded tracks play from disk on every screen.
Album/playlist cards show a downloaded badge; download button resumes missing
songs. Song storage is dedup'd by ID and reference-counted on delete.
Fixes: Android 15 download crash (dropped banned DATA_SYNC foreground service);
offline detail flash-back (initial empty state no longer mistaken for deleted).
Docs: CHANGELOG 0.10 + parity matrix; condensed README Features.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
HoneyandClaude Opus 4.8
73fcfae30f