be9700-api: correct exposure/security note in description

apps/be9700-api/metadata/description.md

@@ -25,9 +25,11 @@ Every request to `/api/*` must carry:
 | `X-Router-Password` | Router admin password (for fresh sessions) |
 | `X-Router-Session` | Reuse a session token returned by a previous call (JSON) |
 
-This means the container itself holds no secrets and is safe to expose via
-Traefik without any additional auth middleware — just use the API from clients
-that supply the headers.
+The container holds no stored secrets, but the `/api/*` surface controls your
+router and CORS is open — anyone who can reach the service and supply a valid
+router password can change router settings. Keep this app LAN-only unless you
+place an auth middleware (e.g. Traefik forward-auth / Authentik) in front of it
+before exposing it to the internet.
 
 ## Quick start