Add CONTROL_SERVER_HOST to allow external connections

- Add CONTROL_SERVER_HOST environment variable (default: 0.0.0.0)
- Server now binds to all interfaces by default for external access
- Update .env and .env.example with new host configuration
- Allows UI clients to connect from other machines on the network

src/control_server.py

@@ -376,10 +376,11 @@ class ControlServer:
 
     async def start_websocket_server(self):
         """Start WebSocket server for UI clients."""
+        host = os.getenv("CONTROL_SERVER_HOST", "0.0.0.0")
         server = await websockets.serve(
-            self.handle_ui_client, "localhost", CONTROL_SERVER_PORT
+            self.handle_ui_client, host, CONTROL_SERVER_PORT
         )
-        logging.info(f"WebSocket server listening on localhost:{CONTROL_SERVER_PORT}")
+        logging.info(f"WebSocket server listening on {host}:{CONTROL_SERVER_PORT}")
 
     async def run(self):
         """Run the control server."""