refactor: 文件行数超标拆解（Service + Controller 9/16 完成）

- Service 层：energy_service → energize/operations/admin/query 四文件
- Service 层：post_service → helpers/audit + 核心 CRUD 保留
- Service 层：favorite_service → items + 核心文件夹操作保留
- Service 层：auth_service → password + 核心注册/登录保留
- Service 层：notification_service → notify + 核心列表/已读保留
- Service 层：audit_service → review + 核心列表/详情保留
- Controller 层：studio_controller → page/write/api/post_api/action 五文件
- Controller 层：post_controller → page/api/upload 三文件
- Controller 层：comment_controller → list/write/action/upload 四文件
- 清理未使用导入（notification_service.go 移除 fmt）

internal/service/audit_review.go

@@ -0,0 +1,104 @@
+package service
+
+import (
+	"metazone.cc/metalab/internal/common"
+	"metazone.cc/metalab/internal/model"
+
+	"gorm.io/gorm"
+)
+
+// review 通用审核操作
+func (s *AuditService) review(reviewerID uint, submissionID uint, approved bool, reason string) error {
+	// 1. 查审核记录
+	submission, err := s.auditRepo.FindByID(submissionID)
+	if err != nil {
+		if err == gorm.ErrRecordNotFound {
+			return common.ErrAuditNotFound
+		}
+		return err
+	}
+
+	// 2. 必须 pending
+	if submission.Status != model.AuditStatusPending {
+		return common.ErrAuditNotPending
+	}
+
+	// 3. 查审核人信息
+	reviewer, err := s.userRepo.FindByID(reviewerID)
+	if err != nil {
+		return common.ErrUserNotFound
+	}
+
+	// 4. 标记审核结果
+	submission.ReviewedBy = &reviewerID
+	submission.ReviewerName = &reviewer.Username
+	if approved {
+		submission.Status = model.AuditStatusApproved
+		// 更新 User 表对应字段
+		if err := s.applyApproval(submission); err != nil {
+			return err
+		}
+		// 通知用户审核通过
+		if s.notifier != nil {
+			s.notifier.NotifyAuditApproved(submission.UserID, submission.AuditType, submission.ID)
+		}
+	} else {
+		submission.Status = model.AuditStatusRejected
+		submission.RejectReason = &reason
+		// 通知用户审核被拒（改名审核追加域能返还提示）
+		if s.notifier != nil {
+			reasonMsg := reason
+			if submission.AuditType == model.AuditTypeUsername {
+				reasonMsg += "。扣除的域能已被返还"
+			}
+			s.notifier.NotifyAuditRejected(submission.UserID, submission.AuditType, reasonMsg, submission.ID)
+		}
+		// 改名审核被拒 → 返还域能
+		if submission.AuditType == model.AuditTypeUsername && s.energyRefundSvc != nil {
+			_ = s.energyRefundSvc.RefundOnRenameReject(submission.UserID)
+		}
+	}
+	return s.auditRepo.Update(submission)
+}
+
+// applyApproval 将审核通过的内容写入 User 表
+// 用户名审批前再次检查冲突（防止提交到审批期间被其他用户抢占）
+func (s *AuditService) applyApproval(submission *model.AuditSubmission) error {
+	user, err := s.userRepo.FindByID(submission.UserID)
+	if err != nil {
+		return common.ErrUserNotFound
+	}
+
+	switch submission.AuditType {
+	case model.AuditTypeUsername:
+		exists, err := s.userRepo.ExistsByUsername(submission.NewValue)
+		if err != nil {
+			return err
+		}
+		if exists {
+			return common.ErrUsernameTaken
+		}
+		user.Username = submission.NewValue
+	case model.AuditTypeAvatar:
+		user.Avatar = submission.NewValue
+	case model.AuditTypeBio:
+		user.Bio = submission.NewValue
+	}
+	if err := s.userRepo.Update(user); err != nil {
+		return err
+	}
+
+	// 触发首次任务奖励（静默失败不影响主流程）
+	if s.levelSvc != nil {
+		switch submission.AuditType {
+		case model.AuditTypeUsername:
+			_, _, _ = s.levelSvc.CompleteTask(submission.UserID, "username")
+		case model.AuditTypeAvatar:
+			_, _, _ = s.levelSvc.CompleteTask(submission.UserID, "avatar")
+		case model.AuditTypeBio:
+			_, _, _ = s.levelSvc.CompleteTask(submission.UserID, "bio")
+		}
+	}
+
+	return nil
+}