refactor: split music streaming into Hope Music

Move the media server, downloader, library volume, and browser player to the
standalone hope-media-music product. Keep Hope's music tools as a thin HTTP
client of the LAN service on port 8094.

Use a stable voice-room player scope instead of ephemeral LiveKit room names.
The agent now owns the conversation handshake: fresh reported playback mutes
its input, joining pauses music, and the last participant leaving resumes only
music it paused. Peer failures remain non-fatal.

Also move the voice deploy workflow onto the active Unraid Gitea runner and
remove yt-dlp/ffmpeg/media health and volume dependencies from the image.

supervisord.conf

@@ -56,18 +56,3 @@ environment=
     LIVEKIT_API_SECRET="%(ENV_LIVEKIT_API_SECRET)s",
     VOICE_USERS_FILE="%(ENV_VOICE_USERS_FILE)s",
     VOICE_DEFAULT_USER="%(ENV_VOICE_DEFAULT_USER)s"
-
-[program:media-server]
-; Runs as root because the /data/media bind mount is a host (Unraid) share
-; whose uid does not match the container's voiceuser.
-; MEDIA_DIR / MEDIA_SERVER_PORT / YTDLP_COOKIES are inherited from the
-; container environment (media_server.py has safe defaults for all three) —
-; do NOT list them via %(ENV_x)s here: a missing var aborts supervisord's
-; config expansion and takes every program down with it.
-command=/opt/voice-agent/.venv/bin/python /opt/voice/media_server.py
-user=root
-autostart=true
-autorestart=true
-stdout_logfile=/dev/stdout
-stdout_logfile_maxbytes=0
-redirect_stderr=true