feat: 重构内容和订单列表接口，使用过滤器结构体简化参数传递；更新相关服务和测试用例

backend/app/services/content.go

@@ -23,14 +23,14 @@ func (s *content) List(ctx context.Context, filter *content_dto.ContentListFilte
 
 	// Filters
 	q = q.Where(tbl.Status.Eq(consts.ContentStatusPublished))
-	if filter.Keyword != "" {
-		q = q.Where(tbl.Title.Like("%" + filter.Keyword + "%"))
+	if filter.Keyword != nil && *filter.Keyword != "" {
+		q = q.Where(tbl.Title.Like("%" + *filter.Keyword + "%"))
 	}
-	if filter.Genre != "" {
-		q = q.Where(tbl.Genre.Eq(filter.Genre))
+	if filter.Genre != nil && *filter.Genre != "" {
+		q = q.Where(tbl.Genre.Eq(*filter.Genre))
 	}
-	if filter.TenantID != "" {
-		tid := cast.ToInt64(filter.TenantID)
+	if filter.TenantID != nil && *filter.TenantID != "" {
+		tid := cast.ToInt64(*filter.TenantID)
 		q = q.Where(tbl.TenantID.Eq(tid))
 	}
 
@@ -38,7 +38,12 @@ func (s *content) List(ctx context.Context, filter *content_dto.ContentListFilte
 	q = q.Preload(tbl.Author)
 
 	// Sort
-	switch filter.Sort {
+	sort := "latest"
+	if filter.Sort != nil && *filter.Sort != "" {
+		sort = *filter.Sort
+	}
+
+	switch sort {
 	case "hot":
 		q = q.Order(tbl.Views.Desc())
 	case "price_asc":
@@ -48,7 +53,6 @@ func (s *content) List(ctx context.Context, filter *content_dto.ContentListFilte
 	}
 
 	// Pagination
-	// Use embedded pagination directly
 	filter.Pagination.Format()
 	total, err := q.Count()
 	if err != nil {