refactor: 清理死代码 + 修复ISP接口注释

- 移除未使用的DTO类型(ChangePasswordRequest/DeleteAccountRequest)
- 移除service层未引用的错误重导出(auth_service/audit_service)
- 删除未使用的SiteSettingRepo(数据访问由config.SiteSettings直接处理)
- 删除未使用的FindByStatus方法(user_repo)
- 删除未使用的AutoMigrate方法(audit_repo/notification_repo)
- 删除未使用的PaginatedResult/NewPaginatedResult(pagination.go)
- 修复接口注释：notifProvider(5→4)、auditUseCase(4→3)、siteSettingUseCase(3→4)
- 移除auditStatusProvider未使用的FindByUsername方法
- 统一使用common.ErrXxx直接引用，消除跨service错误重导出耦合

internal/common/pagination.go

@@ -8,15 +8,6 @@ type Pagination struct {
 	PageSize int `form:"page_size" json:"page_size" binding:"min=1,max=100"`
 }
 
-// PaginatedResult 分页响应
-type PaginatedResult struct {
-	Items      interface{} `json:"items"`
-	Total      int64       `json:"total"`
-	Page       int         `json:"page"`
-	PageSize   int         `json:"page_size"`
-	TotalPages int         `json:"total_pages"`
-}
-
 // DefaultPagination 默认分页（未传参时使用）
 func (p *Pagination) DefaultPagination() {
 	if p.Page < 1 {
@@ -32,20 +23,5 @@ func (p *Pagination) Offset() int {
 	return (p.Page - 1) * p.PageSize
 }
 
-// NewPaginatedResult 构建分页响应
-func NewPaginatedResult(items interface{}, total int64, page, pageSize int) *PaginatedResult {
-	totalPages := int(total) / pageSize
-	if int(total)%pageSize > 0 {
-		totalPages++
-	}
-	return &PaginatedResult{
-		Items:      items,
-		Total:      total,
-		Page:       page,
-		PageSize:   pageSize,
-		TotalPages: totalPages,
-	}
-}
-
 // 固定时间格式，前后端统一
 const TimeFormat = time.RFC3339

internal/controller/admin/interfaces.go

@@ -13,14 +13,14 @@ type adminUseCase interface {
 	CountUsers() (int64, error)
 }
 
-// auditUseCase AuditController 对 AuditService 的最小依赖（ISP：4 个方法）
+// auditUseCase AuditController 对 AuditService 的最小依赖（ISP：3 个方法）
 type auditUseCase interface {
 	List(auditType, status string, page, pageSize int) (*service.AuditListResult, error)
 	Approve(reviewerID uint, submissionID uint) error
 	Reject(reviewerID uint, submissionID uint, reason string) error
 }
 
-// siteSettingUseCase SiteSettingController 对 SiteSettingService 的最小依赖（ISP：3 个方法）
+// siteSettingUseCase SiteSettingController 对 SiteSettingService 的最小依赖（ISP：4 个方法）
 type siteSettingUseCase interface {
 	GetSettings() map[string]string
 	UpdateSetting(key, value string) error
@@ -31,5 +31,4 @@ type siteSettingUseCase interface {
 // auditStatusProvider 审核控制器所需的用户信息查询（ISP）
 type auditStatusProvider interface {
 	FindByID(id uint) (*model.User, error)
-	FindByUsername(username string) (*model.User, error)
 }

internal/controller/message_controller.go

@@ -10,7 +10,7 @@ import (
 	"github.com/gin-gonic/gin"
 )
 
-// notifProvider MessageController 所需的通知服务接口（ISP：5 个方法）
+// notifProvider MessageController 所需的通知服务接口（ISP：4 个方法）
 type notifProvider interface {
 	List(userID uint, page, pageSize int) (*model.NotificationListResult, error)
 	CountUnread(userID uint) (int64, error)

internal/model/dto.go

@@ -20,14 +20,4 @@ type CheckEmailRequest struct {
 	Email string `json:"email" binding:"required,email"`
 }
 
-// ChangePasswordRequest 修改密码请求
-type ChangePasswordRequest struct {
-	CurrentPassword string `json:"current_password" binding:"required"`
-	NewPassword     string `json:"new_password" binding:"required,min=8"`
-}
 
-// DeleteAccountRequest 注销账号请求
-type DeleteAccountRequest struct {
-	Password string `json:"password" binding:"required"`
-	Reason   string `json:"reason"`
-}

internal/repository/audit_repo.go

@@ -16,11 +16,6 @@ func NewAuditRepo(db *gorm.DB) *AuditRepo {
 	return &AuditRepo{db: db}
 }
 
-// AutoMigrate 自动迁移审核表
-func (r *AuditRepo) AutoMigrate() error {
-	return r.db.AutoMigrate(&model.AuditSubmission{})
-}
-
 // Create 创建审核提交
 func (r *AuditRepo) Create(audit *model.AuditSubmission) error {
 	return r.db.Create(audit).Error

internal/repository/notification_repo.go

@@ -16,11 +16,6 @@ func NewNotificationRepo(db *gorm.DB) *NotificationRepo {
 	return &NotificationRepo{db: db}
 }
 
-// AutoMigrate 自动迁移消息表
-func (r *NotificationRepo) AutoMigrate() error {
-	return r.db.AutoMigrate(&model.Notification{})
-}
-
 // Create 创建消息
 func (r *NotificationRepo) Create(n *model.Notification) error {
 	return r.db.Create(n).Error

internal/repository/site_setting_repo.go

@@ -1,34 +0,0 @@
-package repository
-
-import (
-	"metazone.cc/metalab/internal/model"
-
-	"gorm.io/gorm"
-)
-
-// SiteSettingRepo 站点设置数据访问
-type SiteSettingRepo struct {
-	db *gorm.DB
-}
-
-// NewSiteSettingRepo 构造函数
-func NewSiteSettingRepo(db *gorm.DB) *SiteSettingRepo {
-	return &SiteSettingRepo{db: db}
-}
-
-// AutoMigrate 自动迁移站点设置表
-func (r *SiteSettingRepo) AutoMigrate() error {
-	return r.db.AutoMigrate(&model.SiteSetting{})
-}
-
-// Upsert 创建或更新站点设置
-func (r *SiteSettingRepo) Upsert(key, value string) error {
-	return r.db.Save(&model.SiteSetting{Key: key, Value: value}).Error
-}
-
-// GetAll 获取所有站点设置
-func (r *SiteSettingRepo) GetAll() ([]model.SiteSetting, error) {
-	var settings []model.SiteSetting
-	err := r.db.Find(&settings).Error
-	return settings, err
-}

internal/repository/user_repo.go

@@ -170,9 +170,3 @@ func (r *UserRepo) CountSearchUsers(keyword, role, status string) (int64, error)
 	return count, err
 }
 
-// FindByStatus 按状态分页查询（回收站用，暂未暴露前端）
-func (r *UserRepo) FindByStatus(status string, offset, limit int) ([]model.User, error) {
-	var users []model.User
-	err := r.db.Where("status = ?", status).Order("uid ASC").Offset(offset).Limit(limit).Find(&users).Error
-	return users, err
-}

internal/service/audit_service.go

@@ -59,14 +59,6 @@ func NewAuditService(auditRepo auditRepo, userRepo userProfileStore, settings si
 	}
 }
 
-// ErrXxx 重导出
-var (
-	ErrAuditNotFound   = common.ErrAuditNotFound
-	ErrAuditNotPending = common.ErrAuditNotPending
-	ErrAuditDisabled   = common.ErrAuditDisabled
-	ErrAuditTypeOff    = common.ErrAuditTypeOff
-)
-
 // ShouldAudit 判断指定用户是否需要走审核流程
 // 规则：admin 及以上角色免审
 func (s *AuditService) ShouldAudit(userID uint) (bool, error) {
@@ -85,12 +77,12 @@ func (s *AuditService) ShouldAudit(userID uint) (bool, error) {
 func (s *AuditService) Submit(userID uint, auditType, newValue string) error {
 	// 检查总开关
 	if !s.settings.IsAuditEnabled() {
-		return ErrAuditDisabled
+		return common.ErrAuditDisabled
 	}
 
 	// 检查类型开关
 	if !s.settings.IsAuditTypeEnabled(auditType, s.typeDefault(auditType)) {
-		return ErrAuditTypeOff
+		return common.ErrAuditTypeOff
 	}
 
 	// 用户名冲突检查（提交时即拦截，避免提交到后台后审核失败）
@@ -101,7 +93,7 @@ func (s *AuditService) Submit(userID uint, auditType, newValue string) error {
 			return err
 		}
 		if exists {
-			return ErrUsernameTaken
+			return common.ErrUsernameTaken
 		}
 		// 2) 审核表中已有其他用户提交了同名 pending
 		pendingExists, err := s.auditRepo.ExistsPendingByTypeAndValue(auditType, newValue, userID)
@@ -109,7 +101,7 @@ func (s *AuditService) Submit(userID uint, auditType, newValue string) error {
 			return err
 		}
 		if pendingExists {
-			return ErrUsernameTaken
+			return common.ErrUsernameTaken
 		}
 	}
 
@@ -164,14 +156,14 @@ func (s *AuditService) review(reviewerID uint, submissionID uint, approved bool,
 	submission, err := s.auditRepo.FindByID(submissionID)
 	if err != nil {
 		if err == gorm.ErrRecordNotFound {
-			return ErrAuditNotFound
+			return common.ErrAuditNotFound
 		}
 		return err
 	}
 
 	// 2. 必须 pending
 	if submission.Status != model.AuditStatusPending {
-		return ErrAuditNotPending
+		return common.ErrAuditNotPending
 	}
 
 	// 3. 查审核人信息
@@ -220,7 +212,7 @@ func (s *AuditService) applyApproval(submission *model.AuditSubmission) error {
 			return err
 		}
 		if exists {
-			return ErrUsernameTaken
+			return common.ErrUsernameTaken
 		}
 		user.Username = submission.NewValue
 	case model.AuditTypeAvatar:

internal/service/auth_service.go

@@ -25,24 +25,6 @@ func NewAuthService(userRepo userAuthStore, tokenSvc tokenProvider, cfg *config.
 	return &AuthService{userRepo: userRepo, tokenService: tokenSvc, cfg: cfg}
 }
 
-var (
-	ErrEmailExists        = common.ErrEmailExists
-	ErrUsernameTaken      = common.ErrUsernameTaken
-	ErrInvalidCred        = common.ErrInvalidCred
-	ErrUserNotFound       = common.ErrUserNotFound
-	ErrUserBanned         = common.ErrUserBanned
-	ErrUserLocked         = common.ErrUserLocked
-	ErrUserDeleted        = common.ErrUserDeleted
-	ErrWeakPassword       = common.ErrWeakPassword
-	ErrTokenExpired       = common.ErrTokenExpired
-	ErrTokenInvalid       = common.ErrTokenInvalid
-	ErrTokenRevoked       = common.ErrTokenRevoked
-	ErrPermissionDenied   = common.ErrPermissionDenied
-	ErrIncorrectPassword   = common.ErrIncorrectPassword
-	ErrNeedsConfirmRestore = common.ErrNeedsConfirmRestore
-	ErrOwnerCannotDelete   = common.ErrOwnerCannotDelete
-)
-
 var pwLetter = regexp.MustCompile(`[a-zA-Z]`)
 var pwDigit = regexp.MustCompile(`\d`)
 
@@ -64,7 +46,7 @@ func init() {
 // validatePassword 密码强度：至少 8 位 + 包含字母 + 包含数字
 func validatePassword(pw string) error {
 	if len(pw) < 8 || !pwLetter.MatchString(pw) || !pwDigit.MatchString(pw) {
-		return ErrWeakPassword
+		return common.ErrWeakPassword
 	}
 	return nil
 }
@@ -85,7 +67,7 @@ func (s *AuthService) Register(req model.RegisterRequest, regIP string) (string,
 		return "", "", nil, err
 	}
 	if exists {
-		return "", "", nil, ErrEmailExists
+		return "", "", nil, common.ErrEmailExists
 	}
 
 	// 3. 哈希密码
@@ -138,31 +120,31 @@ func (s *AuthService) Login(req model.LoginRequest, loginIP string) (string, str
 	user, err := s.userRepo.FindByEmail(req.Email)
 	if err != nil {
 		_ = bcrypt.CompareHashAndPassword(dummyHash, []byte(req.Password))
-		return "", "", nil, ErrInvalidCred
+		return "", "", nil, common.ErrInvalidCred
 	}
 
 	// 已注销（deleted）→ 验证密码后要求二次确认，不自动恢复
 	if user.Status == model.StatusDeleted {
 		if !common.CheckPassword(req.Password, user.PasswordHash) {
 			_ = bcrypt.CompareHashAndPassword(dummyHash, []byte(req.Password))
-			return "", "", nil, ErrInvalidCred
+			return "", "", nil, common.ErrInvalidCred
 		}
-		return "", "", nil, ErrNeedsConfirmRestore
+		return "", "", nil, common.ErrNeedsConfirmRestore
 	}
 
 	// 永久锁定
 	if user.Status == model.StatusLocked {
 		_ = bcrypt.CompareHashAndPassword(dummyHash, []byte(req.Password))
-		return "", "", nil, ErrUserLocked
+		return "", "", nil, common.ErrUserLocked
 	}
 
 	// 封禁
 	if user.Status == model.StatusBanned {
-		return "", "", nil, ErrUserBanned
+		return "", "", nil, common.ErrUserBanned
 	}
 
 	if !common.CheckPassword(req.Password, user.PasswordHash) {
-		return "", "", nil, ErrInvalidCred
+		return "", "", nil, common.ErrInvalidCred
 	}
 
 	// 记录登录 IP 和时间
@@ -194,16 +176,16 @@ func (s *AuthService) ConfirmRestore(req model.LoginRequest, loginIP string) (st
 	user, err := s.userRepo.FindByEmail(req.Email)
 	if err != nil {
 		_ = bcrypt.CompareHashAndPassword(dummyHash, []byte(req.Password))
-		return "", "", nil, ErrInvalidCred
+		return "", "", nil, common.ErrInvalidCred
 	}
 
 	// 仅 deleted 状态允许恢复
 	if user.Status != model.StatusDeleted {
-		return "", "", nil, ErrUserNotFound
+		return "", "", nil, common.ErrUserNotFound
 	}
 
 	if !common.CheckPassword(req.Password, user.PasswordHash) {
-		return "", "", nil, ErrInvalidCred
+		return "", "", nil, common.ErrInvalidCred
 	}
 
 	// 恢复账号
@@ -249,7 +231,7 @@ func (s *AuthService) ChangePassword(userID uint, currentPassword, newPassword s
 
 	// 验证当前密码
 	if !common.CheckPassword(currentPassword, user.PasswordHash) {
-		return ErrIncorrectPassword
+		return common.ErrIncorrectPassword
 	}
 
 	// 新密码强度校验
@@ -282,12 +264,12 @@ func (s *AuthService) DeleteAccount(userID uint, password, reason string) error
 
 	// 站长不允许自主注销（避免权限体系死锁）
 	if user.Role == model.RoleOwner {
-		return ErrOwnerCannotDelete
+		return common.ErrOwnerCannotDelete
 	}
 
 	// 验证当前密码（防止 CSRF 或未授权操作）
 	if !common.CheckPassword(password, user.PasswordHash) {
-		return ErrIncorrectPassword
+		return common.ErrIncorrectPassword
 	}
 
 	user.Status = model.StatusDeleted

internal/service/token_service.go

@@ -74,24 +74,24 @@ func (ts *TokenService) BuildRefreshToken(user *model.User, rememberMe bool) (st
 // 校验 token_version：若 DB 中版本已递增，拒绝刷新 → 即时吊销
 func (ts *TokenService) RefreshAccessToken(refreshTokenStr string) (string, *model.User, error) {
 	if refreshTokenStr == "" {
-		return "", nil, ErrTokenInvalid
+		return "", nil, common.ErrTokenInvalid
 	}
 
 	token, err := jwt.Parse(refreshTokenStr, func(t *jwt.Token) (interface{}, error) {
 		return []byte(ts.cfg.JWT.Secret), nil
 	})
 	if err != nil || !token.Valid {
-		return "", nil, ErrTokenExpired
+		return "", nil, common.ErrTokenExpired
 	}
 
 	claims, ok := token.Claims.(jwt.MapClaims)
 	if !ok {
-		return "", nil, ErrTokenInvalid
+		return "", nil, common.ErrTokenInvalid
 	}
 
 	// 只接受 refresh 用途的 token，防止 access token 被用于刷新
 	if purpose, _ := claims["purpose"].(string); purpose != "refresh" {
-		return "", nil, ErrTokenInvalid
+		return "", nil, common.ErrTokenInvalid
 	}
 
 	uid := uint(claims["uid"].(float64))