fix: preserve real cancellation in MCP paths

tests/agent/test_task_cancel.py

@@ -111,6 +111,34 @@ class TestHandleStop:
 
 
 class TestDispatch:
+    @pytest.mark.asyncio
+    async def test_run_logs_and_continues_after_leaked_cancelled_error(self, monkeypatch):
+        loop, bus = _make_loop()
+        loop._connect_mcp = AsyncMock()
+        loop.close_mcp = AsyncMock()
+        loop.auto_compact.check_expired = MagicMock()
+        warnings: list[str] = []
+        calls = 0
+
+        async def consume_once_then_stop():
+            nonlocal calls
+            calls += 1
+            if calls == 1:
+                raise asyncio.CancelledError()
+            loop.stop()
+            raise asyncio.TimeoutError()
+
+        monkeypatch.setattr(bus, "consume_inbound", consume_once_then_stop)
+        monkeypatch.setattr(
+            "nanobot.agent.loop.logger.warning",
+            lambda message, *args, **kwargs: warnings.append(message),
+        )
+
+        await loop.run()
+
+        assert calls == 2
+        assert any("Ignoring leaked CancelledError" in warning for warning in warnings)
+
     def test_exec_tool_not_registered_when_disabled(self):
         from nanobot.agent.tools.shell import ExecToolConfig
         from nanobot.config.schema import ToolsConfig