feat: add tests and better model validation for gesture commands

ref: N25B-334

src/control_backend/agents/communication/ri_communication_agent.py

@@ -193,6 +193,7 @@ class RICommunicationAgent(BaseAgent):
                         gesture_data=gesture_data,
                     )
                     await robot_speech_agent.start()
+                    await asyncio.sleep(0.1)  # Small delay
                     await robot_gesture_agent.start()
                 case _:
                     self.logger.warning("Unhandled negotiation id: %s", id)