test(赛马插件): 修复模拟测试中的竞态条件

在测试模拟赛马时，添加对 CancelledError 的异常处理，防止任务取消导致测试挂起。同时修复 stop_race 方法的模拟，确保测试清理时能正确移除活动任务。

danding_bot/plugins/group_horse_racing/test_commands.py

@@ -214,6 +214,7 @@ async def handle_test_simulate_race(bot: Bot, event: Event):
     original_points_service = commands_mod.points_service
     original_message_service = commands_mod.message_service
     original_tick_interval = commands_mod.config.RACE_TICK_INTERVAL
+    original_stop_race = commands_mod.race_engine.stop_race
 
 
     fake_room_store = _InMemoryRoomStore()
@@ -230,6 +231,7 @@ async def handle_test_simulate_race(bot: Bot, event: Event):
         commands_mod.points_service = fake_points_service
         commands_mod.message_service = fake_message_service
         commands_mod.config.RACE_TICK_INTERVAL = 0
+        commands_mod.race_engine.stop_race = lambda _scope: commands_mod.race_engine.active_tasks.pop(_scope, None)
 
         room = fake_room_store.create_room(scope)
         horse_names = _generate_random_horse_names(8)
@@ -304,6 +306,9 @@ async def handle_test_simulate_race(bot: Bot, event: Event):
     except asyncio.TimeoutError:
         ticks = room.tick_count if room else 0
         await test_simulate_race_cmd.finish(f"完全模拟失败：超时未完成（当前回合：{ticks}）")
+    except asyncio.CancelledError:
+        ticks = room.tick_count if room else 0
+        await test_simulate_race_cmd.finish(f"完全模拟失败：任务被取消（当前回合：{ticks}）")
     except Exception as e:
         tail = "\n".join(traceback.format_exc().splitlines()[-8:])
         await test_simulate_race_cmd.finish(f"完全模拟异常：{type(e).__name__}: {e}\n{tail}")
@@ -314,3 +319,4 @@ async def handle_test_simulate_race(bot: Bot, event: Event):
         commands_mod.points_service = original_points_service
         commands_mod.message_service = original_message_service
         commands_mod.config.RACE_TICK_INTERVAL = original_tick_interval
+        commands_mod.race_engine.stop_race = original_stop_race