refactor: 文件行数超标拆解（7个文件→14个文件，全部≤200行）

- 移动本地接口定义到 interfaces.go 和 admin/interfaces.go
- favorite_controller.go → favorite_item_controller.go
- space_controller.go → space_loaders.go
- settings_controller.go → settings_api_audit.go
- admin_energy_controller.go → admin_energy_api_controller.go
- admin_post_controller.go → admin_post_action_controller.go
- comment_repo.go → comment_mention_repo.go
- post_repo.go → post_stats_repo.go

internal/repository/comment_mention_repo.go

@@ -0,0 +1,137 @@
+package repository
+
+import (
+	"strconv"
+
+	"metazone.cc/metalab/internal/model"
+	"metazone.cc/metalab/internal/service"
+)
+
+// CreateMention 创建@提及记录
+func (r *CommentRepo) CreateMention(mention *model.CommentMention) error {
+	return r.db.Create(mention).Error
+}
+
+// FindMentionsByComment 查询某条评论的@提及列表
+func (r *CommentRepo) FindMentionsByComment(commentID uint) ([]model.CommentMention, error) {
+	var list []model.CommentMention
+	err := r.db.Where("comment_id = ?", commentID).Find(&list).Error
+	return list, err
+}
+
+// SearchUsersByLevel 搜索指定等级及以上用户（用于@艾特），返回 uid/username/exp
+func (r *CommentRepo) SearchUsersByLevel(keyword string, minLevel int, limit int) ([]struct {
+	UID      string
+	Username string
+	Exp      int
+}, error) {
+	type result struct {
+		UID      uint
+		Username string
+		Exp      int
+	}
+	var list []result
+
+	threshold := model.LevelThresholds[minLevel]
+
+	err := r.db.Table("users").
+		Select("uid, username, exp").
+		Where("username LIKE ? AND exp >= ? AND deleted_at IS NULL", "%"+keyword+"%", threshold).
+		Order("exp DESC").
+		Limit(limit).
+		Find(&list).Error
+
+	var res []struct {
+		UID      string
+		Username string
+		Exp      int
+	}
+	for _, u := range list {
+		res = append(res, struct {
+			UID      string
+			Username string
+			Exp      int
+		}{UID: strconv.FormatUint(uint64(u.UID), 10), Username: u.Username, Exp: u.Exp})
+	}
+	return res, err
+}
+
+// GetUserUIDByID 通过 uint ID 获取 user 的 UID 字符串
+func (r *CommentRepo) GetUserUIDByID(userID uint) (string, error) {
+	var uid uint
+	err := r.db.Table("users").Select("uid").Where("uid = ?", userID).Scan(&uid).Error
+	if err != nil {
+		return "", err
+	}
+	return strconv.FormatUint(uint64(uid), 10), nil
+}
+
+// GetUsernameByID 通过 userID 获取用户名（用于通知内容）
+func (r *CommentRepo) GetUsernameByID(userID uint) (string, error) {
+	var username string
+	err := r.db.Table("users").Select("username").Where("uid = ?", userID).Scan(&username).Error
+	return username, err
+}
+
+// FindPostIDByComment 查询评论所属的文章ID
+func (r *CommentRepo) FindPostIDByComment(commentID uint) (uint, error) {
+	var postID uint
+	err := r.db.Table("comments").Select("post_id").Where("id = ?", commentID).Scan(&postID).Error
+	return postID, err
+}
+
+// UpdateRootID 更新评论的 root_id 字段（顶级评论创建后回填）
+func (r *CommentRepo) UpdateRootID(id, rootID uint) error {
+	return r.db.Model(&model.Comment{}).Where("id = ?", id).Update("root_id", rootID).Error
+}
+
+// FindPostAuthorID 查询文章的作者 user_id
+func (r *CommentRepo) FindPostAuthorID(postID uint) (uint, error) {
+	var authorID uint
+	err := r.db.Table("posts").Select("user_id").Where("id = ?", postID).Scan(&authorID).Error
+	return authorID, err
+}
+
+// AggregateCommentsByAuthor 按日期聚合评论量（作者所有文章在时间段内的评论）
+func (r *CommentRepo) AggregateCommentsByAuthor(userID uint, since string) ([]service.TrendPoint, error) {
+	var results []service.TrendPoint
+	err := r.db.Table("comments").
+		Select("TO_CHAR(comments.created_at, 'YYYY-MM-DD') AS date, COUNT(*) AS value").
+		Joins("JOIN posts ON posts.id = comments.post_id").
+		Where("posts.user_id = ? AND comments.created_at >= ?", userID, since).
+		Group("TO_CHAR(comments.created_at, 'YYYY-MM-DD')").
+		Order("date ASC").
+		Scan(&results).Error
+	if results == nil {
+		results = []service.TrendPoint{}
+	}
+	return results, err
+}
+
+// ListAllComments 后台评论列表（支持关键词搜索、分页）
+func (r *CommentRepo) ListAllComments(keyword string, showDeleted bool, offset, limit int) ([]model.AdminCommentRow, int64, error) {
+	var total int64
+	q := r.db.Table("comments").
+		Joins("LEFT JOIN users ON users.uid = comments.user_id").
+		Joins("LEFT JOIN posts ON posts.id = comments.post_id")
+
+	if !showDeleted {
+		q = q.Where("comments.is_deleted = false")
+	}
+	if keyword != "" {
+		like := "%" + keyword + "%"
+		q = q.Where("comments.body LIKE ? OR users.username LIKE ? OR posts.title LIKE ?", like, like, like)
+	}
+
+	if err := q.Count(&total).Error; err != nil {
+		return nil, 0, err
+	}
+
+	var rows []model.AdminCommentRow
+	err := q.
+		Select("comments.id, comments.post_id, posts.title as post_title, comments.body, users.username as author_name, comments.is_deleted, comments.created_at, comments.updated_at").
+		Order("comments.created_at DESC").
+		Offset(offset).Limit(limit).
+		Scan(&rows).Error
+	return rows, total, err
+}