refactor: remove voice/recording/media features from frontend + prune lockfiles

- Delete pages: (dashboard)/{recordings,voice,media}/ incl. view.tsx
- Delete components/{voice,media}, hooks/{use-voice,use-recordings,use-media},
  lib/audio/ (mic-transmit, pcm-player, wav), api/{voice,recordings,media},
  types/{voice,recording,media}, lib/hash.ts
- Cut nav tiles (Active Voice Stages, Voice Recording Archive) from dashboard,
  MiniPlayer from ambient-app, hooks/types barrel exports, WS voice/media events
- Re-home guilds + textChannels to messages oRPC router (DB-derived) so the
  messages page picker keeps working; guild-picker simplified to text-only
- Clean Channel/AppConfig types of voice remnants
- Delete infra/docker/recordings/ + 11 voice/recording/video spec docs
- pnpm install: prune direct voice deps from gateway + backend lockfiles
  (prism-media/opusscript remain only as transitive discord.js deps)

infra/docker/recordings/.gitignore

@@ -1,3 +0,0 @@
-*
-!.gitkeep
-!README.md

infra/docker/recordings/README.md

@@ -1,15 +0,0 @@
-# Recordings Directory
-
-This directory is mounted as a volume in the discord-gateway container.
-Voice recordings are stored here with the following structure:
-
-```
-recordings/
-  ├── <user-id>/
-  │   ├── <timestamp>.ogg
-  │   └── <timestamp>.json
-  └── sessions/
-      └── <session-id>.json
-```
-
-The directory must be writable by UID 1000 (app user in the container).