feat(repository): enhance repository methods with batch processing and transaction support

- Updated Like and Unlike methods in CommentRepository to use transactions for data consistency.
- Introduced IsLikedBatch method for batch checking if comments are liked, addressing N+1 query issues.
- Enhanced BatchDelete method in PostRepository to perform batch deletions within a single transaction, improving efficiency.
- Added BatchUpdateStatus method for posts to utilize a single SQL update for status changes, reducing database load.
- Implemented BatchUpdateSortOrder in StickerRepository using CASE WHEN for efficient sorting updates.
- Added IsFollowingBatch and IsBlockedBatch methods in UserRepository for batch checking follow and block relationships, optimizing performance.

internal/repository/user_repo.go

@@ -140,6 +140,36 @@ func (r *UserRepository) IsFollowing(followerID, followingID string) (bool, erro
 	return count > 0, nil
 }
 
+// IsFollowingBatch 批量检查当前用户是否关注了目标用户（解决 N+1 问题）
+// 返回 map[targetUserID]bool
+func (r *UserRepository) IsFollowingBatch(followerID string, targetUserIDs []string) (map[string]bool, error) {
+	result := make(map[string]bool)
+	if len(targetUserIDs) == 0 || followerID == "" {
+		return result, nil
+	}
+
+	// 初始化所有目标用户为 false
+	for _, id := range targetUserIDs {
+		result[id] = false
+	}
+
+	// 一次性查询所有关注记录
+	var followingIDs []string
+	err := r.db.Model(&model.Follow{}).
+		Where("follower_id = ? AND following_id IN ?", followerID, targetUserIDs).
+		Pluck("following_id", &followingIDs).Error
+	if err != nil {
+		return nil, err
+	}
+
+	// 更新已关注的用户
+	for _, id := range followingIDs {
+		result[id] = true
+	}
+
+	return result, nil
+}
+
 // IncrementFollowersCount 增加用户粉丝数
 func (r *UserRepository) IncrementFollowersCount(userID string) error {
 	return r.db.Model(&model.User{}).Where("id = ?", userID).
@@ -243,6 +273,36 @@ func (r *UserRepository) IsBlocked(blockerID, blockedID string) (bool, error) {
 	return count > 0, nil
 }
 
+// IsBlockedBatch 批量检查拉黑关系（解决 N+1 问题）
+// 返回 map[blockedUserID]bool
+func (r *UserRepository) IsBlockedBatch(blockerID string, blockedIDs []string) (map[string]bool, error) {
+	result := make(map[string]bool)
+	if len(blockedIDs) == 0 || blockerID == "" {
+		return result, nil
+	}
+
+	// 初始化所有目标用户为 false
+	for _, id := range blockedIDs {
+		result[id] = false
+	}
+
+	// 一次性查询所有拉黑记录
+	var blockedUserIDs []string
+	err := r.db.Model(&model.UserBlock{}).
+		Where("blocker_id = ? AND blocked_id IN ?", blockerID, blockedIDs).
+		Pluck("blocked_id", &blockedUserIDs).Error
+	if err != nil {
+		return nil, err
+	}
+
+	// 更新已拉黑的用户
+	for _, id := range blockedUserIDs {
+		result[id] = true
+	}
+
+	return result, nil
+}
+
 // IsBlockedEitherDirection 检查是否任一方向存在拉黑
 func (r *UserRepository) IsBlockedEitherDirection(userA, userB string) (bool, error) {
 	var count int64