chore: import upstream snapshot with attribution

server/state.py

@@ -0,0 +1,37 @@
+"""Global state shared across server modules."""
+
+from typing import Optional
+
+from server.services.websocket_manager import WebSocketManager
+from utils.exceptions import ValidationError
+
+websocket_manager: Optional[WebSocketManager] = None
+
+
+def init_state() -> None:
+    """Ensure global singletons are ready for incoming requests."""
+
+    get_websocket_manager()
+
+
+def get_websocket_manager() -> WebSocketManager:
+    global websocket_manager
+    if websocket_manager is None:
+        websocket_manager = WebSocketManager()
+    return websocket_manager
+
+
+def ensure_known_session(session_id: str, *, require_connection: bool = False) -> WebSocketManager:
+    """Return the WebSocket manager if the session is connected or known."""
+
+    manager = get_websocket_manager()
+    if not session_id:
+        raise ValidationError("Session not connected", details={"session_id": session_id})
+
+    if session_id in manager.active_connections:
+        return manager
+
+    if not require_connection and manager.session_store.has_session(session_id):
+        return manager
+
+    raise ValidationError("Session not connected", details={"session_id": session_id})