fix: attach litellm to shared dashboard network

Connect LiteLLM to nas-dashboard_internal and point dashboard-dev to the litellm container hostname so health probes work without host-loopback routing.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

litellm/docker-compose.yml

@@ -13,6 +13,8 @@ services:
       - "127.0.0.1:${LITELLM_PORT:-4005}:4005"
     volumes:
       - ./config:/config:ro
+    networks:
+      - nas-dashboard_internal
     command:
       - "--config"
       - "/config/litellm.yaml"
@@ -25,3 +27,7 @@ services:
       options:
         max-size: "10m"
         max-file: "3"
+
+networks:
+  nas-dashboard_internal:
+    external: true