fix: remove Request param from _check() — WebSocket can't resolve Request dependency

The Request parameter caused TypeError on WebSocket routes because
FastAPI cannot inject Request into WebSocket scope. Reverted to
parameterless _check(). WebSocket 403 is handled by CSRF middleware
which already skips WebSocket upgrade requests.

app/deps.py

@@ -237,11 +237,7 @@ def require_active_plugin(plugin_name: str):
     already have their own auth dependencies (require_permission, etc.).
     This check only verifies plugin activation status.
     """
-    async def _check(request: Request) -> None:
-        # Skip plugin check for WebSocket connections — WS auth is handled
-        # inside the endpoint itself via session cookie verification.
-        if request.headers.get("upgrade", "").lower() == "websocket":
-            return
+    async def _check() -> None:
         from app.core.permission_registry import get_permission_registry
         try:
             registry = get_permission_registry()