The upstream galaxy/livekit_server role never publishes port 7880 (HTTP
signaling) to the host — it assumes a Traefik container on the same Docker
network. This breaks setups where nginx runs on a separate host and proxies
to the Matrix server over LAN.

Changes:
- Fork galaxy/livekit_server → roles/custom/livekit_server/ so the patch
  survives `make roles` (which wipes roles/galaxy/)
- Add livekit_server_container_http_host_bind_port variable (defaults to "")
  in defaults/main.yml; when set, publishes the HTTP port via -p flag
- Add {% if livekit_server_container_http_host_bind_port %} block in the
  systemd service template to conditionally map the port
- Guard network-creation tasks with `and livekit_server_container_network != 'host'`
  to prevent 403 errors when network: host is configured
- Update setup.yml: galaxy/livekit_server → custom/livekit_server

Usage in vars.yml:
  livekit_server_container_http_host_bind_port: '192.168.90.83:7880'

https://claude.ai/code/session_01SbRgWsRDKpTZ2TTbWDhtEB