fix(权限管理): 增强权限检查的类型安全并修复权限引用

修复权限检查中可能传入非Permission类型导致的错误，将echo插件的权限引用从MessageEvent.ADMIN迁移到Permission.ADMIN

plugins/echo.py

@@ -6,6 +6,7 @@ Echo 与交互插件
 from core.managers.command_manager import matcher
 from core.bot import Bot
 from models.events.message import MessageEvent
+from core.permission import Permission
 
 __plugin_meta__ = {
     "name": "echo",
@@ -13,7 +14,7 @@ __plugin_meta__ = {
     "usage": "/echo [内容] - 复读内容\n/赞我 - 让机器人给你点赞",
 }
 
-@matcher.command("echo",permission=MessageEvent.ADMIN)
+@matcher.command("echo", permission=Permission.ADMIN)
 async def handle_echo(bot: Bot, event: MessageEvent, args: list[str]):
     """
     处理 echo 指令，原样回复用户输入的内容