Recover stalled database connections and skip unreachable chat recipients

main.py

@@ -336,8 +336,9 @@ async def main():
     
     # Запускаем polling
     try:
-        from src.core.health import HEARTBEAT, heartbeat
+        from src.core.health import HEARTBEAT, heartbeat, start_watchdog
         HEARTBEAT.unlink(missing_ok=True)
+        watchdog = start_watchdog()
         if REDIS_URL:
             await storage.redis.ping()
         from sqlalchemy import select
@@ -345,12 +346,15 @@ async def main():
         async with async_session_maker() as session:
             await session.execute(select(User).limit(0))
         await bot.get_me()
-        health_task = asyncio.create_task(heartbeat())
+        health_task = asyncio.create_task(heartbeat(), name="database-heartbeat")
         logger.info("Бот запущен")
         polling_task = asyncio.create_task(dp.start_polling(bot))
         completed, _ = await asyncio.wait({health_task, polling_task}, return_when=asyncio.FIRST_COMPLETED)
         for task in completed:
             await task
+    except Exception:
+        logger.exception("Runtime supervision failed; stopping the application")
+        raise
     finally:
         from src.core.database import close_db
         from contextlib import suppress
@@ -366,6 +370,8 @@ async def main():
         await bot.session.close()
         await storage.close()
         await close_db()
+        if "watchdog" in locals():
+            watchdog.set()
 
 
 if __name__ == "__main__":