Refactor the websocket message handler

backend/websocket/registry.py

@@ -0,0 +1,33 @@
+from typing import Callable
+
+
+class WebSocketHandlerRegistry:
+    """Registry for WebSocket message handlers with authentication support."""
+    
+    def __init__(self):
+        self._handlers: dict[str, tuple[Callable, bool]] = {}
+    
+    def register(self, message_type: str, authRequired: bool = True):
+        """Register a handler for a message type.
+        
+        Args:
+            message_type: The WebSocket message type to handle
+            authRequired: If True, handler will receive authenticated User (not None) or raise 401
+        """
+        def decorator(func: Callable):
+            self._handlers[message_type] = (func, authRequired)
+            return func
+        return decorator
+    
+    def get_handler(self, message_type: str) -> tuple[Callable, bool] | None:
+        """Get handler and authRequired flag for a message type.
+        
+        Returns:
+            Tuple of (handler function, authRequired flag) or None if not found
+        """
+        return self._handlers.get(message_type)
+    
+    def get_all_types(self) -> list[str]:
+        """Get all registered message types for debugging/logging."""
+        return list(self._handlers.keys())
+