fix type hints

src/teams_ctrl.py

@@ -264,13 +264,13 @@ class TeamsCtrl:
         while not self.loop.is_closed():
             await self.current_state.process()
 
-    def gather_all(self):
+    def gather_all(self) -> asyncio.Future[tuple[None, None, None]]:
         return asyncio.gather(
             self.process_serial(), self.process_ws(), self.process_statemachine()
         )
 
 
-async def amain():
+async def amain() -> None:
     loop = asyncio.get_event_loop()
     serial = await serial_asyncio.open_serial_connection(
         loop=loop, url=args.port, baudrate=115200