Clean up Matrix RTC reverse-proxy docs and nginx example

- 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>

docs/configuring-playbook-matrix-rtc.md

@@ -38,9 +38,11 @@ matrix_rtc_enabled: true
 
 In addition to the HTTP/HTTPS ports (which you've already exposed as per the [prerequisites](prerequisites.md) document), you'll also need to open ports required by [LiveKit Server](configuring-playbook-livekit-server.md) as described in its own [Adjusting firewall rules](configuring-playbook-livekit-server.md#adjusting-firewall-rules) section.
 
-### Behind a reverse proxy
-If you are behind an additional reverse proxy like nginx it needs to forward websockets for livekit.
+## Fronting the integrated reverse-proxy with another reverse-proxy
 
+If you're [fronting the integrated reverse-proxy webserver with another reverse-proxy](configuring-playbook-own-webserver.md#fronting-the-integrated-reverse-proxy-webserver-with-another-reverse-proxy) (e.g. nginx), it needs to forward WebSocket traffic for [LiveKit Server](configuring-playbook-livekit-server.md) at the `/livekit-server/` path. Without that, Matrix RTC calls will not work.
+
+See [`examples/reverse-proxies/nginx/matrix.conf`](../examples/reverse-proxies/nginx/matrix.conf) for an nginx example.
 
 ## Installing
 

examples/reverse-proxies/nginx/matrix.conf

@@ -21,8 +21,9 @@ server {
     # if you don't use those, you can remove them
     # if you use e.g. Etherpad on etherpad.example.com, add etherpad.example.com to the server_name list
     server_name example.com matrix.example.com element.example.com;
-   
-    # needed for matrix rtc
+
+    # Required for Matrix RTC (WebSocket proxying to LiveKit Server).
+    # See: ../../../docs/configuring-playbook-matrix-rtc.md#fronting-the-integrated-reverse-proxy-with-another-reverse-proxy
     location /livekit-server/ {
         proxy_pass http://localhost:81/livekit-server/;
         proxy_http_version 1.1;
@@ -42,7 +43,6 @@ server {
         error_log /var/log/nginx/matrix.error.log;
     }
 
-
     location / {
         # note: do not add a path (even a single /) after the port in `proxy_pass`,
         # otherwise, nginx will canonicalise the URI and cause signature verification