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.

tests/conftest.py

@@ -27,8 +27,7 @@ WEB_BASE_URL = os.environ.get("VOICE_WEB_URL", "https://192.168.86.2:9178").rstr
 TOKEN_URL = os.environ.get(
     "VOICE_TOKEN_URL", f"{WEB_BASE_URL}/token"
 )
-# Filesystem-coupled tests (repo ./media bind mount) only make sense when
-# the test host IS the deployment host.
+# docker-exec integration probes only make sense when the test target is local.
 IS_LOCAL_DEPLOYMENT = urlparse(WEB_BASE_URL).hostname in ("localhost", "127.0.0.1")
 LLM_BASE_URL = (
     os.environ.get("LLM_BASE_URL")