Add internal Traefik ingress for Pangolin and Authelia

docs/architecture/NETWORKING_MODEL.md

@@ -64,6 +64,14 @@ networks:
     external: true
 ```
 
+### Internal Ingress Pattern
+- Pangolin remains the public edge on the VPS.
+- PD now runs an internal-only Traefik container on the `pangolin` network.
+- Secure routed apps should move toward: `Pangolin -> Traefik -> app`.
+- Traefik does not mount `docker.sock`; routes are explicit file-provider config.
+- Authelia is the policy decision point for per-domain and per-group access.
+- Internal services can stay HTTP-only behind Traefik unless a backend specifically needs HTTPS.
+
 ### Internal Service Model
 Internal services run HTTP only behind the reverse proxy. Compose service names used for internal DNS between services in the same stack/network.