Replace ripped Discord audio with self-authored Ogg Vorbis files (avoids
copyright on open-source launch) and fix three cue bugs:
- Anti-pop envelope: playSound now applies a 10ms fade-in (+ tail fade-out
for one-shots) so buffers no longer start at a non-zero amplitude. Kills
the pop on the looping call cues. Mirrors playTestTone.
- Deafen no longer plays mute+deafen at once: toggleDeafen flips isMuted and
isDeafened atomically, so SoundController saw both transitions. New tested
pure helper selectVoiceStateSound() suppresses the side-effect mute cue.
- Viewer-side watch feedback: stream_user_joined/left now play locally on the
watcher's own machine for explicit Watch/Stop actions, via
handleViewerWatchToggle. Direct local playback (not a watchingStreams diff)
keeps auto-teardown silent and works identically on Safari and Electron.
Docs: docs/systems/sounds.md updated (Ogg, dual-audience cue rows, mute/deafen
selection, viewer feedback, anti-pop envelope).
Jannis Braun