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/http/v1/dto/content.go

@@ -4,10 +4,10 @@ import "quyun/v2/app/requests"
 
 type ContentListFilter struct {
 	requests.Pagination
-	Keyword  string `query:"keyword"`
-	Genre    string `query:"genre"`
-	TenantID string `query:"tenantId"`
-	Sort     string `query:"sort"`
+	Keyword  *string `query:"keyword"`
+	Genre    *string `query:"genre"`
+	TenantID *string `query:"tenantId"`
+	Sort     *string `query:"sort"`
 }
 
 type ContentItem struct {