feat: implement new structure

backend/app/http/v1/dto/order.go

@@ -0,0 +1,23 @@
+package dto
+
+type OrderCreateForm struct {
+	ContentID string `json:"contentId"`
+	Sku       string `json:"sku"`
+	Quantity  int    `json:"quantity"`
+}
+
+type OrderCreateResponse struct {
+	OrderID string `json:"orderId"`
+}
+
+type OrderPayForm struct {
+	Method string `json:"method"` // wechat, alipay, balance
+}
+
+type OrderPayResponse struct {
+	PayParams string `json:"payParams"`
+}
+
+type OrderStatusResponse struct {
+	Status string `json:"status"` // unpaid, paid, completed
+}