chore: 初始化脚手架 — sunny_mochi 企业级 Flutter 模板

Core 基础设施：Flavor 三包体系、Drift+SQLCipher 加密数据库
7 拦截器 Dio 网络栈、CrashReporter 崩溃日志、Sealed Failure 错误体系
5 色板主题系统、Auth 认证骨架（Clean Architecture）、Dev Panel、Mock Adapter

通过验证：flutter analyze（0 errors）、flutter test（全绿）、staging APK 74.8MB

lib/features/auth/data/models/user_model.dart

@@ -0,0 +1,42 @@
+import 'package:freezed_annotation/freezed_annotation.dart';
+import 'package:sunny_mochi/features/auth/domain/entities/user_entity.dart';
+
+part 'user_model.freezed.dart';
+part 'user_model.g.dart';
+
+@freezed
+abstract class UserModel with _$UserModel {
+  const factory UserModel({
+    String? userId,
+    String? username,
+    String? realName,
+    String? phone,
+    String? avatar,
+    String? token,
+    String? tokenName,
+    String? refreshToken,
+    String? email,
+    DateTime? birthday,
+    int? gender,
+    String? employeeNo,
+    String? company,
+    String? department,
+  }) = _UserModel;
+
+  factory UserModel.fromJson(Map<String, dynamic> json) =>
+      _$UserModelFromJson(json);
+}
+
+extension UserModelX on UserModel {
+  UserEntity toEntity() => UserEntity(
+        userId: userId,
+        username: username,
+        realName: realName,
+        phone: phone,
+        avatar: avatar,
+        token: token,
+        employeeNo: employeeNo,
+        company: company,
+        department: department,
+      );
+}