Fix WebSocket handler for websockets 15.x compatibility

Remove path parameter from handle_client() method to fix compatibility
with websockets library version 15.x which no longer passes the path
argument to connection handlers.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/server/websocket_handler.py

@@ -28,13 +28,11 @@ class WebSocketHandler:
     async def handle_client(
         self,
         websocket: WebSocketServerProtocol,
-        path: str,
     ) -> None:
         """Handle a WebSocket client connection.
 
         Args:
             websocket: WebSocket connection
-            path: Request path (unused)
         """
         # Generate player ID (will be replaced when JOIN message received)
         import uuid