refactor: remove voice, recording, and music/media features (gateway + backend)
- Gateway: delete voice-recording/, voice-pcm-ws/, voice/video/media handlers,
vendor/discord-voice-fork/, voice DB repos, 2 voice migrations
- Gateway: cut voice wiring from bootstrap/shutdown/commandHandler/handler-registry,
eventBroadcaster/eventTypes, redis-channels, moderation-types, message-capture,
config keys, and deps (@discordjs/voice, opus, libsodium, prism-media, davey)
- Backend: delete voice/, recordings/, media/ modules + @discordjs/voice dep
- Backend: cut voice/media/recordings oRPC routers, WS gateway-PCM auth + voice
handlers, Redis bridge voice aggregation, redis-channels voice/media constants,
config keys, moderation-types voice items, e2e voice/recordings suites
- Keep voice DB tables (destructive migration avoided); chatbot voiceRecordings
tool + dashboard count remain as read-only historical data access