fix: use different port, fix endpoint name matching

ref: N25B-168

src/robot_interface/endpoints/main_receiver.py

@@ -53,7 +53,7 @@ class MainReceiver(ReceiverBase):
 
         if message["endpoint"] == "ping":
             return self._handle_ping(message)
-        elif message["endpoint"].startswith("negotiation"):
+        elif message["endpoint"].startswith("negotiate"):
             return self._handle_negotiation(message)
 
         return {"endpoint": "error", "data": "The requested endpoint is not supported."}