Replace wpctl volume control with SDL_mixer VolumeMusic
Remove all PipeWire/wpctl system calls (SetDefaultSinkVolume,
listSinkIDs, listSinks, SetAllSinkVolumes, parseSinks, parseSinkLine,
Sink struct). Volume is now managed entirely through SDL_mixer's
VolumeMusic(), making audio fully system-agnostic.
Changes:
- mixer.go: delete ~170 lines of wpctl code; add SetVolume() public
API using mix.VolumeMusic(math.Round(level * MAX_VOLUME))
- Init/Play/SwitchDevice set volume inline (they already hold the mutex)
- Play() now uses stored currentVolume instead of hardcoded MAX_VOLUME
- AudioOptions: SetAllSinkVolumes -> SetVolume
- mixer_test.go: add TestSetVolume (validation + error path coverage)
NeilClack
3480e7594a