Add admin panel, WebSocket support, and API versioning

Introduce an admin portal (React + Nginx), WebSocket routing, and
API versioning middleware with `/api/v1/` prefix deprecation.
Add master API key authentication, new Prometheus metrics for AI
token consumption and active WebSockets, and extend S3 config
with a public endpoint URL. Update test paths and fixtures to
align with the new routing structure.

pytest.ini

@@ -5,4 +5,6 @@ python_files = test_*.py
 python_functions = test_*
 filterwarnings =
     ignore::DeprecationWarning
-    
+env =
+    STORAGE_BACKEND=local
+    REDIS_URL=redis://localhost:6379/1