fix(review): use AsyncMock for async _open_kitchen_handler in test

test_cold_open_kitchen_runs_handler patched _open_kitchen_handler with
MagicMock, but production code awaits it. await None raises TypeError.
Switch to AsyncMock so the mock returns an awaitable.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Trecek

tests/server/test_open_kitchen_deferred_recall.py

@@ -4,7 +4,7 @@
 
 import json
 from pathlib import Path
-from unittest.mock import MagicMock, patch
+from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
 
@@ -376,7 +376,7 @@ async def test_cold_open_kitchen_runs_handler():
     with (
         patch("autoskillit.server._get_ctx", return_value=mock_ctx),
         patch.object(
-            tools_kitchen, "_open_kitchen_handler", new_callable=MagicMock
+            tools_kitchen, "_open_kitchen_handler", new_callable=AsyncMock
         ) as mock_handler,
     ):
         mock_handler.return_value = None