docs: add Related sections to remaining platform, reference template, and misc pages

docs/web/dashboard.md

@@ -91,3 +91,8 @@ Prefer localhost, Tailscale Serve, or an SSH tunnel.
   then connect.
 - The UI language picker is in **Overview -> Gateway Access -> Language**.
   It is part of the access card, not the Appearance section.
+
+## Related
+
+- [Control UI](/web/control-ui)
+- [WebChat](/web/webchat)

docs/web/webchat.md

@@ -73,3 +73,8 @@ Related global options:
 - `gateway.auth.mode: "trusted-proxy"`: reverse-proxy auth for browser clients behind an identity-aware **non-loopback** proxy source (see [Trusted Proxy Auth](/gateway/trusted-proxy-auth)).
 - `gateway.remote.url`, `gateway.remote.token`, `gateway.remote.password`: remote gateway target.
 - `session.*`: session storage and main key defaults.
+
+## Related
+
+- [Control UI](/web/control-ui)
+- [Dashboard](/web/dashboard)