feat: Refactor user context handling and service methods

- Updated middleware to fetch user and tenant models by ID and set them in context.
- Refactored common service methods to accept userID as a parameter instead of extracting from context.
- Modified content service methods to include userID as a parameter for better clarity and performance.
- Adjusted coupon, creator, notification, order, tenant, user, and wallet services to utilize userID directly.
- Enhanced context key constants for improved readability and maintainability.

backend/app/services/coupon.go

@@ -15,12 +15,11 @@ import (
 // @provider
 type coupon struct{}
 
-func (s *coupon) ListUserCoupons(ctx context.Context, status string) ([]coupon_dto.UserCouponItem, error) {
-	userID := ctx.Value(consts.CtxKeyUser)
-	if userID == nil {
+func (s *coupon) ListUserCoupons(ctx context.Context, userID int64, status string) ([]coupon_dto.UserCouponItem, error) {
+	if userID == 0 {
 		return nil, errorx.ErrUnauthorized
 	}
-	uid := cast.ToInt64(userID)
+	uid := userID
 
 	tbl, q := models.UserCouponQuery.QueryContext(ctx)
 	q = q.Where(tbl.UserID.Eq(uid))