- Move the reverse-proxy note in matrix-rtc.md out from under "Adjusting
  firewall rules" (not a firewall topic) into its own top-level section.
- Rewrite the text to explain what actually needs to happen (WebSocket
  forwarding at `/livekit-server/`) and link to the nginx example.
- Cross-link from the nginx example back to the docs section.
- Fix trailing whitespace and an extra blank line in matrix.conf.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>