refactor(plugin_system): 统一事件和处理器相关方法的类型注解

将事件管理器中多个方法的类型注解从 `type[BaseEventHandler]` 调整为 `BaseEventHandler`，以反映其处理的是处理器实例而非类本身。同时，优化了事件名称的处理逻辑，确保在整个系统中对 `EventType` 枚举和字符串类型名称的处理保持一致性。

- 将 `_event_handlers` 的类型注解从 `dict[str, type[BaseEventHandler]]` 修改为 `dict[str, BaseEventHandler]`
- 相应地更新了 `get_event_handler` 和 `get_all_event_handlers` 方法的返回类型注解
- 在多个方法内部增加了对 `EventType` 枚举的处理，使其能够接受枚举成员作为参数，提高了类型安全性和代码可读性

src/plugin_system/core/event_manager.py

@@ -37,7 +37,7 @@ class EventManager:
             return
 
         self._events: dict[str, BaseEvent] = {}
-        self._event_handlers: dict[str, type[BaseEventHandler]] = {}
+        self._event_handlers: dict[str, BaseEventHandler] = {}
         self._pending_subscriptions: dict[str, list[str]] = {}  # 缓存失败的订阅
         self._scheduler_callback: Any | None = None  # scheduler 回调函数
         self._initialized = True
@@ -62,16 +62,17 @@ class EventManager:
             allowed_triggers = []
         if allowed_subscribers is None:
             allowed_subscribers = []
-        if event_name in self._events:
-            logger.warning(f"事件 {event_name} 已存在，跳过注册")
+        _event_name = event_name.value if isinstance(event_name, EventType) else event_name
+        if _event_name in self._events:
+            logger.warning(f"事件 {_event_name} 已存在，跳过注册")
             return False
 
-        event = BaseEvent(event_name, allowed_subscribers, allowed_triggers)
-        self._events[event_name] = event
-        logger.debug(f"事件 {event_name} 注册成功")
+        event = BaseEvent(_event_name, allowed_subscribers, allowed_triggers)
+        self._events[_event_name] = event
+        logger.debug(f"事件 {_event_name} 注册成功")
 
         # 检查是否有缓存的订阅需要处理
-        self._process_pending_subscriptions(event_name)
+        self._process_pending_subscriptions(_event_name)
 
         return True
 
@@ -84,7 +85,8 @@ class EventManager:
         Returns:
             BaseEvent: 事件实例，不存在返回None
         """
-        return self._events.get(event_name)
+        _event_name = event_name.value if isinstance(event_name, EventType) else event_name
+        return self._events.get(_event_name)
 
     def get_all_events(self) -> dict[str, BaseEvent]:
         """获取所有已注册的事件
@@ -175,10 +177,11 @@ class EventManager:
 
         # 处理init_subscribe，缓存失败的订阅
         if self._event_handlers[handler_name].init_subscribe:
-            failed_subscriptions = [
-                event_name for event_name in self._event_handlers[handler_name].init_subscribe
-                if not self.subscribe_handler_to_event(handler_name, event_name)
-            ]
+            failed_subscriptions: list[str] = []
+            for event_name in self._event_handlers[handler_name].init_subscribe:
+                if not self.subscribe_handler_to_event(handler_name, event_name):
+                    _event_name = event_name.value if isinstance(event_name, EventType) else event_name
+                    failed_subscriptions.append(_event_name)
 
             # 缓存失败的订阅
             if failed_subscriptions:
@@ -188,22 +191,22 @@ class EventManager:
         logger.info(f"事件处理器 {handler_name} 注册成功")
         return True
 
-    def get_event_handler(self, handler_name: str) -> type[BaseEventHandler] | None:
+    def get_event_handler(self, handler_name: str) -> BaseEventHandler | None:
         """获取指定事件处理器实例
 
         Args:
             handler_name (str): 处理器名称
 
         Returns:
-            Type[BaseEventHandler]: 处理器实例，不存在返回None
+            BaseEventHandler: 处理器实例，不存在返回None
         """
         return self._event_handlers.get(handler_name)
 
-    def get_all_event_handlers(self) -> dict[str, type[BaseEventHandler]]:
+    def get_all_event_handlers(self) -> dict[str, BaseEventHandler]:
         """获取所有已注册的事件处理器
 
         Returns:
-            Dict[str, Type[BaseEventHandler]]: 所有处理器的字典
+            Dict[str, BaseEventHandler]: 所有处理器的字典
         """
         return self._event_handlers.copy()
 
@@ -383,7 +386,7 @@ class EventManager:
             "pending_subscriptions": len(self._pending_subscriptions),
         }
 
-    def _process_pending_subscriptions(self, event_name: EventType | str) -> None:
+    def _process_pending_subscriptions(self, event_name: str) -> None:
         """处理指定事件的缓存订阅
 
         Args: