Refactor type annotations and router initialization

Standardized type annotations for interfaces in user.ts and improved type safety in webapi.ts. Updated all Express router initializations to explicitly declare the Router type. Added missing RequestHandler typings in uploader modules for better type checking.

packages/napcat-webui-backend/src/router/index.ts

@@ -19,7 +19,7 @@ import DebugRouter from '@/napcat-webui-backend/src/api/Debug';
 import { ProcessRouter } from './Process';
 import { PluginRouter } from './Plugin';
 
-const router = Router();
+const router: Router = Router();
 
 // 鉴权中间件
 router.use(auth);