feat: 就地通过评审，并为已过审用户提供默认可关的免审发布

帖/评管理入口可直接通过；站点默认信任已有 published 内容的用户后续直发。

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/service/moderation.go

@@ -280,6 +280,26 @@ func (s *ModerationService) RejectComment(actor *Actor, id uint) error {
 	})
 }
 
+// UserHasApprovedContent 用户是否已有至少一篇已发布帖子或一条已发布评论（即曾通过审核或免审直发）
+func (s *ModerationService) UserHasApprovedContent(userID uint) (bool, error) {
+	var n int64
+	if err := s.db.Model(&model.Post{}).
+		Where("user_id = ? AND status = ?", userID, model.ContentStatusPublished).
+		Limit(1).Count(&n).Error; err != nil {
+		return false, err
+	}
+	if n > 0 {
+		return true, nil
+	}
+	n = 0
+	if err := s.db.Model(&model.Comment{}).
+		Where("user_id = ? AND status = ?", userID, model.ContentStatusPublished).
+		Limit(1).Count(&n).Error; err != nil {
+		return false, err
+	}
+	return n > 0, nil
+}
+
 func keys(m map[uint]bool) []uint {
 	out := make([]uint, 0, len(m))
 	for k := range m {