refactor: 重构后端架构为 go-zero 框架，优化项目结构

主要变更:
- 采用 go-zero 框架替代 Gin，提升开发效率
- 重构项目结构，API 文件模块化组织
- 将 model 移至 api/internal/model 目录
- 移除 common 包，改为标准 pkg 目录结构
- 实现统一的仓储模式，支持配置驱动数据库切换
- 简化测试策略，专注 API 集成测试
- 更新 CLAUDE.md 文档，提供详细的开发指导

技术栈更新:
- 框架: Gin → go-zero v1.6.0+
- 代码生成: 引入 goctl 工具
- 架构模式: 四层架构 → go-zero 三层架构 (Handler→Logic→Model)
- 项目布局: 遵循 Go 社区标准和 go-zero 最佳实践

backend/internal/service/auth/auth_service.go

@@ -3,7 +3,8 @@ package auth
 import (
 	"fmt"
 	"golang.org/x/crypto/bcrypt"
-	"photography-backend/internal/models"
+	"photography-backend/internal/model/entity"
+	"photography-backend/internal/model/dto"
 	"photography-backend/internal/repository/postgres"
 )
 
@@ -22,23 +23,15 @@ func NewAuthService(userRepo postgres.UserRepository, jwtService *JWTService) *A
 }
 
 // Login 用户登录
-func (s *AuthService) Login(req *models.LoginRequest) (*models.LoginResponse, error) {
+func (s *AuthService) Login(req *dto.LoginRequest) (*dto.LoginResponse, error) {
 	// 根据用户名或邮箱查找用户
-	var user *models.User
+	var user *entity.User
 	var err error
 	
-	// 尝试按用户名查找
-	user, err = s.userRepo.GetByUsername(req.Username)
+	// 按邮箱查找用户
+	user, err = s.userRepo.GetByEmail(req.Email)
 	if err != nil {
-		return nil, fmt.Errorf("failed to get user: %w", err)
-	}
-	
-	// 如果用户名未找到，尝试按邮箱查找
-	if user == nil {
-		user, err = s.userRepo.GetByEmail(req.Username)
-		if err != nil {
-			return nil, fmt.Errorf("failed to get user by email: %w", err)
-		}
+		return nil, fmt.Errorf("failed to get user by email: %w", err)
 	}
 	
 	if user == nil {
@@ -56,7 +49,7 @@ func (s *AuthService) Login(req *models.LoginRequest) (*models.LoginResponse, er
 	}
 	
 	// 生成JWT令牌
-	tokenPair, err := s.jwtService.GenerateTokenPair(user.ID, user.Username, user.Role)
+	tokenPair, err := s.jwtService.GenerateTokenPair(user.ID, user.Username, string(user.Role))
 	if err != nil {
 		return nil, fmt.Errorf("failed to generate tokens: %w", err)
 	}
@@ -70,17 +63,19 @@ func (s *AuthService) Login(req *models.LoginRequest) (*models.LoginResponse, er
 	// 清除密码字段
 	user.Password = ""
 	
-	return &models.LoginResponse{
-		AccessToken:  tokenPair.AccessToken,
-		RefreshToken: tokenPair.RefreshToken,
-		TokenType:    tokenPair.TokenType,
-		ExpiresIn:    tokenPair.ExpiresIn,
-		User:         user,
+	return &dto.LoginResponse{
+		Token: dto.TokenResponse{
+			AccessToken:  tokenPair.AccessToken,
+			RefreshToken: tokenPair.RefreshToken,
+			TokenType:    tokenPair.TokenType,
+			ExpiresIn:    tokenPair.ExpiresIn,
+		},
+		User: *dto.ConvertToUserResponse(user),
 	}, nil
 }
 
 // Register 用户注册
-func (s *AuthService) Register(req *models.CreateUserRequest) (*models.User, error) {
+func (s *AuthService) Register(req *dto.CreateUserRequest) (*entity.User, error) {
 	// 检查用户名是否已存在
 	existingUser, err := s.userRepo.GetByUsername(req.Username)
 	if err != nil {
@@ -106,7 +101,7 @@ func (s *AuthService) Register(req *models.CreateUserRequest) (*models.User, err
 	}
 	
 	// 创建用户
-	user := &models.User{
+	user := &entity.User{
 		Username: req.Username,
 		Email:    req.Email,
 		Password: string(hashedPassword),
@@ -117,7 +112,7 @@ func (s *AuthService) Register(req *models.CreateUserRequest) (*models.User, err
 	
 	// 如果没有指定角色，默认为普通用户
 	if user.Role == "" {
-		user.Role = models.RoleUser
+		user.Role = entity.UserRoleUser
 	}
 	
 	if err := s.userRepo.Create(user); err != nil {
@@ -131,7 +126,7 @@ func (s *AuthService) Register(req *models.CreateUserRequest) (*models.User, err
 }
 
 // RefreshToken 刷新令牌
-func (s *AuthService) RefreshToken(req *models.RefreshTokenRequest) (*models.LoginResponse, error) {
+func (s *AuthService) RefreshToken(req *dto.RefreshTokenRequest) (*dto.LoginResponse, error) {
 	// 验证刷新令牌
 	claims, err := s.jwtService.ValidateToken(req.RefreshToken)
 	if err != nil {
@@ -154,7 +149,7 @@ func (s *AuthService) RefreshToken(req *models.RefreshTokenRequest) (*models.Log
 	}
 	
 	// 生成新的令牌对
-	tokenPair, err := s.jwtService.GenerateTokenPair(user.ID, user.Username, user.Role)
+	tokenPair, err := s.jwtService.GenerateTokenPair(user.ID, user.Username, string(user.Role))
 	if err != nil {
 		return nil, fmt.Errorf("failed to generate tokens: %w", err)
 	}
@@ -162,17 +157,19 @@ func (s *AuthService) RefreshToken(req *models.RefreshTokenRequest) (*models.Log
 	// 清除密码字段
 	user.Password = ""
 	
-	return &models.LoginResponse{
-		AccessToken:  tokenPair.AccessToken,
-		RefreshToken: tokenPair.RefreshToken,
-		TokenType:    tokenPair.TokenType,
-		ExpiresIn:    tokenPair.ExpiresIn,
-		User:         user,
+	return &dto.LoginResponse{
+		Token: dto.TokenResponse{
+			AccessToken:  tokenPair.AccessToken,
+			RefreshToken: tokenPair.RefreshToken,
+			TokenType:    tokenPair.TokenType,
+			ExpiresIn:    tokenPair.ExpiresIn,
+		},
+		User: *dto.ConvertToUserResponse(user),
 	}, nil
 }
 
 // GetUserByID 根据ID获取用户
-func (s *AuthService) GetUserByID(id uint) (*models.User, error) {
+func (s *AuthService) GetUserByID(id uint) (*entity.User, error) {
 	user, err := s.userRepo.GetByID(id)
 	if err != nil {
 		return nil, fmt.Errorf("failed to get user: %w", err)
@@ -189,7 +186,7 @@ func (s *AuthService) GetUserByID(id uint) (*models.User, error) {
 }
 
 // UpdatePassword 更新密码
-func (s *AuthService) UpdatePassword(userID uint, req *models.UpdatePasswordRequest) error {
+func (s *AuthService) UpdatePassword(userID uint, req *dto.ChangePasswordRequest) error {
 	// 获取用户信息
 	user, err := s.userRepo.GetByID(userID)
 	if err != nil {
@@ -221,11 +218,11 @@ func (s *AuthService) UpdatePassword(userID uint, req *models.UpdatePasswordRequ
 }
 
 // CheckPermission 检查权限
-func (s *AuthService) CheckPermission(userRole string, requiredRole string) bool {
-	roleLevel := map[string]int{
-		models.RoleUser:   1,
-		models.RoleEditor: 2,
-		models.RoleAdmin:  3,
+func (s *AuthService) CheckPermission(userRole entity.UserRole, requiredRole entity.UserRole) bool {
+	roleLevel := map[entity.UserRole]int{
+		entity.UserRoleUser:         1,
+		entity.UserRolePhotographer: 2,
+		entity.UserRoleAdmin:        3,
 	}
 	
 	userLevel, exists := roleLevel[userRole]
@@ -242,11 +239,11 @@ func (s *AuthService) CheckPermission(userRole string, requiredRole string) bool
 }
 
 // IsAdmin 检查是否为管理员
-func (s *AuthService) IsAdmin(userRole string) bool {
-	return userRole == models.RoleAdmin
+func (s *AuthService) IsAdmin(userRole entity.UserRole) bool {
+	return userRole == entity.UserRoleAdmin
 }
 
-// IsEditor 检查是否为编辑者或以上
-func (s *AuthService) IsEditor(userRole string) bool {
-	return userRole == models.RoleEditor || userRole == models.RoleAdmin
+// IsPhotographer 检查是否为摄影师或以上
+func (s *AuthService) IsPhotographer(userRole entity.UserRole) bool {
+	return userRole == entity.UserRolePhotographer || userRole == entity.UserRoleAdmin
 }