OGG Vorbis (vorbisspi+jorbis) per-room music via rooms.yaml, external gitignored
music/ folder. Testable MusicController (idempotent track switch, null->silence,
OFF disables) over an isolated OggMusicBackend; GameIO.setMusic/setMusicLevel
no-op on console, played by SwingIO. Settings gains a Music level Off/Low/Med/High
(default Medium). Console stays silent.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
