优化发布群租客清退与历史消息

backend/internal/modules/chat/message.go

@@ -14,15 +14,11 @@ func (r *Repository) Messages(ctx context.Context, principal Principal, conversa
 	page, pageSize = normalizePagination(page, pageSize)
 	db := r.db.WithContext(ctx)
 
-	var participant *model.ChatParticipant
-
 	// 管理员可以查看任意会话的消息，普通用户需要是 participant
 	if principal.Type != "admin" {
-		p, err := r.findParticipant(db, principal, conversationID, false)
-		if err != nil {
+		if _, err := r.findParticipant(db, principal, conversationID, false); err != nil {
 			return nil, err
 		}
-		participant = p
 	} else {
 		// 管理员需要验证会话存在
 		var count int64
@@ -37,11 +33,6 @@ func (r *Repository) Messages(ctx context.Context, principal Principal, conversa
 	// 构建查询
 	query := db.Model(&model.ChatMessage{}).Where("conversation_id = ?", conversationID)
 
-	// 租客只能看到加入时间之后的消息
-	if principal.Type == "user" && participant != nil && participant.Role == "renter" {
-		query = query.Where("created_at >= ?", participant.JoinedAt)
-	}
-
 	var total int64
 	if err := query.Count(&total).Error; err != nil {
 		return nil, err