fix(telegram): widen fatal handoff to heartbeat watchdog path

The wedged-recovery heartbeat watchdog (line 2526) calls
_notify_fatal_error() directly from the heartbeat task. disconnect()
cancels _polling_heartbeat_task unconditionally (no current_task guard,
unlike _polling_error_task). Same bug class as #68406: the child
disconnect cancels the heartbeat parent before the runner can queue
reconnect.

Widen _handoff_polling_fatal_error() to also clear
_polling_heartbeat_task when it is the current task, and route the
heartbeat watchdog call site through the handoff helper.

Co-authored-by: Imgaojp <6065749+Imgaojp@users.noreply.github.com>

plugins/platforms/telegram/adapter.py

@@ -2523,7 +2523,7 @@ class TelegramAdapter(BasePlatformAdapter):
                             "gateway reconnect." % stuck_for,
                             retryable=True,
                         )
-                        await self._notify_fatal_error()
+                        await self._handoff_polling_fatal_error()
                         return
                 else:
                     stuck_task_ref = None
@@ -2988,15 +2988,17 @@ class TelegramAdapter(BasePlatformAdapter):
         """Notify the runner without letting child teardown cancel this owner.
 
         The runner bounds adapter cleanup in a child task.  ``disconnect()``
-        cancels the tracked polling-recovery task, so retaining the current
-        notifier in ``_polling_error_task`` would cancel the fatal callback
-        before the runner can finish its reconnect or shutdown decision.
-        Release only the current owner; unrelated recovery tasks remain under
-        teardown control.
+        cancels the tracked polling-recovery task and the heartbeat task, so
+        retaining the current notifier in either field would cancel the fatal
+        callback before the runner can finish its reconnect or shutdown
+        decision.  Release only the current owner from whichever field tracks
+        it; unrelated tasks remain under teardown control.
         """
         current_task = asyncio.current_task()
         if self._polling_error_task is current_task:
             self._polling_error_task = None
+        if getattr(self, "_polling_heartbeat_task", None) is current_task:
+            self._polling_heartbeat_task = None
         await self._notify_fatal_error()
 
     async def _create_dm_topic(

tests/gateway/test_telegram_network_reconnect.py

@@ -259,6 +259,42 @@ async def test_retry_exhaustion_queues_reconnect_before_child_disconnect(tmp_pat
     assert runner._failed_platforms[Platform.TELEGRAM]["attempts"] == 0
 
 
+@pytest.mark.asyncio
+async def test_heartbeat_watchdog_handoff_survives_child_disconnect(tmp_path):
+    """The wedged-recovery heartbeat watchdog must survive its fatal callback.
+
+    The heartbeat loop force-escalates a stuck polling-recovery task.  Like
+    the network/conflict terminal paths, the heartbeat task itself is the
+    owner that ``disconnect()`` cancels, so the fatal callback must release
+    ``_polling_heartbeat_task`` before notifying the runner.
+    """
+    config = GatewayConfig(
+        platforms={
+            Platform.TELEGRAM: PlatformConfig(enabled=True, token="test-token")
+        },
+        sessions_dir=tmp_path / "sessions",
+    )
+    runner = GatewayRunner(config)
+    adapter = _make_adapter()
+    adapter.set_fatal_error_handler(runner._handle_adapter_fatal_error)
+    runner.adapters = {Platform.TELEGRAM: adapter}
+    runner.delivery_router.adapters = runner.adapters
+
+    # Simulate the heartbeat watchdog's fatal-escalation path directly.
+    adapter._set_fatal_error(
+        "telegram_network_error",
+        "Telegram reconnect task wedged; forcing gateway reconnect.",
+        retryable=True,
+    )
+    heartbeat_task = asyncio.create_task(adapter._handoff_polling_fatal_error())
+    adapter._polling_heartbeat_task = heartbeat_task
+    result = await asyncio.gather(heartbeat_task, return_exceptions=True)
+
+    assert result == [None]
+    assert runner.adapters == {}
+    assert Platform.TELEGRAM in runner._failed_platforms
+
+
 # ---------------------------------------------------------------------------
 # Connection pool drain tests (PR #16466 salvage)
 # ---------------------------------------------------------------------------