feat(server.py): create a thread for _poll_loop

src/judas_server/backend/server.py

@@ -34,6 +34,9 @@ class BackendServer:
 
     def start_polling(self) -> None:
         self.running = True
+        threading.Thread(
+            name="BackendServer thread", target=self._poll_loop, daemon=True
+        ).start()
 
     def _poll_loop(self) -> None:
         while self.running: