feat:增加服务器接口模块

lib/models/auth.dart

@@ -0,0 +1,14 @@
+import 'package:json_annotation/json_annotation.dart';
+
+part 'auth.g.dart';
+
+@JsonSerializable()
+class Auth {
+  final int userId;
+
+  Auth({required this.userId});
+
+  factory Auth.fromJson(Map<String, dynamic> json) => _$AuthFromJson(json);
+
+  Map<String, dynamic> toJson() => _$AuthToJson(this);
+}