feat: add coupon support to orders and create user_coupons model

- Added CouponID field to Order model to track used coupons.
- Updated order query generation to include CouponID.
- Introduced UserCoupon model to manage user coupon associations.
- Implemented query methods for UserCoupon to facilitate CRUD operations.
- Updated query context and default query setup to include UserCoupon.

backend/app/services/services.gen.go

@@ -1,9 +1,6 @@
 package services
 
 import (
-	"quyun/v2/providers/job"
-	"quyun/v2/providers/storage"
-
 	"gorm.io/gorm"
 )
 
@@ -14,11 +11,10 @@ var (
 	Audit        *audit
 	Common       *common
 	Content      *content
+	Coupon       *coupon
 	Creator      *creator
-	Job          *job.Job
 	Notification *notification
 	Order        *order
-	Storage      *storage.Storage
 	Super        *super
 	Tenant       *tenant
 	User         *user
@@ -32,11 +28,10 @@ type services struct {
 	audit        *audit
 	common       *common
 	content      *content
+	coupon       *coupon
 	creator      *creator
-	job          *job.Job
 	notification *notification
 	order        *order
-	storage      *storage.Storage
 	super        *super
 	tenant       *tenant
 	user         *user
@@ -50,11 +45,10 @@ func (svc *services) Prepare() error {
 	Audit = svc.audit
 	Common = svc.common
 	Content = svc.content
+	Coupon = svc.coupon
 	Creator = svc.creator
-	Job = svc.job
 	Notification = svc.notification
 	Order = svc.order
-	Storage = svc.storage
 	Super = svc.super
 	Tenant = svc.tenant
 	User = svc.user