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>