chore(cleanup): 删除无引用代码与无用资源

lib/pages/auth/auth_binding.dart

@@ -1,6 +0,0 @@
-import 'auth_logic.dart';
-
-/// 与其它页保持一致的三层写法：binding 负责装配，logic 放状态与逻辑，view 只渲染。
-class AuthBinding {
-  AuthLogic create({bool signUpMode = false}) => AuthLogic(signUpMode: signUpMode);
-}