fix: Telegram-Polling-Task sauber canceln + WhatsApp CancelledError beim Shutdown unterdrücken

channels/telegram_channel.py

@@ -21,6 +21,7 @@ class TelegramChannel(BaseChannel):
 
     def __init__(self) -> None:
         self._app: Application | None = None
+        self._polling_task: asyncio.Task | None = None
         self._inbound_callback: Callable[[dict[str, Any]], Awaitable[None]] | None = None
 
     def set_inbound_callback(self, cb: Callable[[dict[str, Any]], Awaitable[None]]) -> None:
@@ -67,14 +68,21 @@ class TelegramChannel(BaseChannel):
 
         await self._app.initialize()
         await self._app.start()
-        # Long-Polling als Background-Task
-        asyncio.create_task(self._polling_loop(), name="telegram-polling")
+        # Long-Polling als Background-Task (Referenz speichern für sauberes Cancel)
+        self._polling_task = asyncio.create_task(self._polling_loop(), name="telegram-polling")
         logger.info("Telegram channel started (long-polling)")
 
     async def stop(self) -> None:
+        # Polling-Task sauber canceln
+        if self._polling_task and not self._polling_task.done():
+            self._polling_task.cancel()
+            try:
+                await self._polling_task
+            except asyncio.CancelledError:
+                pass
+            self._polling_task = None
+
         if self._app:
-            # Korrekte PTB v20+ Shutdown-Reihenfolge:
-            # Erst Updater stoppen, dann Application stoppen/shutdown
             try:
                 if self._app.updater.running:
                     await self._app.updater.stop()