feat: media player API, web player panel, and Hope music MCP

- web/media_server.py: FastAPI service owning the permanent library
  (library.json + ./media volume), yt-dlp YouTube Music search, queued
  download jobs with mp3 transcode (ffmpeg), per-room player desired
  state, and an HTTPS proxy for external live-stream URLs.
- agent/media_mcp.py: Hope tools — search_music, play_song,
  offer_song_choices, pause/resume/stop/skip/seek, now_playing,
  list_library, add_stream.
- agent/agent.py: media toolset wiring + conversation rule (music
  playing disables the agent mic; re-engaging pauses music).
- web UI: slide-out Music panel (search, suggestions, library, live
  stream add, play/pause, ±10s, seek, volume) with a reconciling poller
  and media_state data-channel reports.
- token server returns the minted room name; nginx serves /media/files
  as static (native Range) and proxies /media/api to the media server.
- supervisord runs media-server; compose mounts ./media and adds
  ffmpeg to the image.

docker-compose.yml

@@ -18,12 +18,16 @@ services:
       WEB_PORT: "${WEB_PORT:-9178}"
       VOICE_USERS_FILE: "/etc/hope/users.json"
       VOICE_DEFAULT_USER: "${VOICE_DEFAULT_USER:-shane}"
+      MEDIA_DIR: "/data/media"
+      MEDIA_SERVER_PORT: "${MEDIA_SERVER_PORT:-8092}"
+      YTDLP_COOKIES: "${YTDLP_COOKIES:-}"
     volumes:
       - ./livekit.yaml:/etc/livekit.yaml:ro
       - ./certs:/etc/voice/certs
       - ./skills:/skills
+      - ./media:/data/media
     healthcheck:
-      test: ["CMD-SHELL", "curl -sk https://localhost:$${WEB_PORT:-9178}/ -o /dev/null && curl -s http://localhost:7880/ -o /dev/null"]
+      test: ["CMD-SHELL", "curl -sk https://localhost:$${WEB_PORT:-9178}/ -o /dev/null && curl -s http://localhost:7880/ -o /dev/null && curl -s http://localhost:$${MEDIA_SERVER_PORT:-8092}/media/api/healthz -o /dev/null"]
       interval: 15s
       timeout: 5s
       retries: 3