Mode (off, auto, track, album), target (-18, -16, -14 LUFS) and boost
(within headroom, or fully with a limiter), stored per user on the server
so the web player, the Android app and casts apply the same one.
- Server: user_normalization_prefs (migration 0067), GET/PUT
/api/me/normalization; a whole-body PUT, validated, last write wins.
- Web: Settings > Playback > Volume leveling. Saves at once, restores the
old choice if the save fails, and caches the value for the player.
- Android: Settings card. The device keeps a copy for offline playback
(Room v9 with an explicit migration, so the upgrade wipes nothing).
Writes are offline-first: shown at once, PUT best effort, queued on
failure (NORMALIZATION_SET, collapsed to the newest). A refresh never
overwrites a change still queued.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
