Make usercode terminate properly when resetting the world

simulator/modules/sbot_interface/socket_server.py

@@ -2,7 +2,9 @@
 from __future__ import annotations
 
 import logging
+import os
 import select
+import signal
 import socket
 import sys
 from threading import Event
@@ -193,6 +195,13 @@ def run(self) -> None:
                 except Exception as e:
                     LOGGER.exception(f"Failure in simulated boards: {e}")
 
+        LOGGER.info('Stopping server')
+        for device in self.devices:
+            device.close()
+
+        # Stop the usercode
+        os.kill(os.getpid(), signal.SIGINT)
+
     def links(self) -> dict[str, dict[str, str]]:
         """Return a mapping of asset tags to ports, grouped by board type."""
         return {