feat: 对齐 Waffo 包年/永久结账与客户端席位 API

同步 OpsXShell 档位定价与 Waffo 商品映射，补齐 checkout/webhook/设备列表契约，便于桌面端购买与满席释放。

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

backend/internal/dto/commerce.go

@@ -64,8 +64,10 @@ type OrderResponse struct {
 type CreateOrderRequest struct {
 	CustomerEmail string `json:"customer_email" binding:"required,email"`
 	CustomerName  string `json:"customer_name"`
-	ProductID     uint   `json:"product_id" binding:"required"`
-	PlanID        uint   `json:"plan_id" binding:"required"`
+	ProductID     uint   `json:"product_id"`
+	PlanID        uint   `json:"plan_id"`
+	ProductCode   string `json:"product_code"` // preferred by desktop clients
+	PlanType      string `json:"plan_type"`    // e.g. perpetual
 	DeviceID      string `json:"device_id"`
 	ReturnURL     string `json:"return_url"`
 	CancelURL     string `json:"cancel_url"`
@@ -82,6 +84,39 @@ type CreateOrderResponse struct {
 	ExpiresAt   string  `json:"expires_at"`
 }
 
+// CheckoutRequest desktop-friendly checkout (product_code + email). // Logan.Li
+type CheckoutRequest struct {
+	CustomerEmail string `json:"customer_email" binding:"required,email"`
+	CustomerName  string `json:"customer_name"`
+	ProductCode   string `json:"product_code"`
+	PlanType      string `json:"plan_type"`
+	DeviceID      string `json:"device_id"`
+	ReturnURL     string `json:"return_url"`
+	CancelURL     string `json:"cancel_url"`
+}
+
+// ClaimPurchaseRequest fetch license after payment. // Logan.Li
+type ClaimPurchaseRequest struct {
+	CustomerEmail string `json:"customer_email"`
+	OrderNo       string `json:"order_no"`
+	ProductCode   string `json:"product_code"`
+	DeviceID      string `json:"device_id"`
+}
+
+// ClaimPurchaseResponse returned after successful payment. // Logan.Li
+type ClaimPurchaseResponse struct {
+	LicenseKey string `json:"license_key"`
+	OrderNo    string `json:"order_no,omitempty"`
+	Status     string `json:"status"`
+	Message    string `json:"message,omitempty"`
+}
+
+// ProductWithPlansResponse for GET /v1/products/code/:code // Logan.Li
+type ProductWithPlansResponse struct {
+	Product ProductResponse `json:"product"`
+	Plans   []PlanResponse  `json:"plans"`
+}
+
 // PaymentWebhookRequest 支付回调请求 // Logan.Li
 type PaymentWebhookRequest struct {
 	EventType      string  `json:"event_type" binding:"required"`