feat: add manual fulfillment order creation

backend/internal/model/merchant.go

@@ -40,6 +40,10 @@ const (
 	OrderStatusShipFailed = "ship_failed" // 发货失败（可重试）
 	OrderStatusCancelled  = "cancelled"   // 已取消并退款
 
+	OrderSourceAPI    = "api"    // 商户开放接口创建
+	OrderSourceManual = "manual" // 商户后台人工创建
+	OrderSourceTest   = "test"   // 后台联调测试订单
+
 	WalletLedgerCredit = "credit"
 	WalletLedgerDebit  = "debit"
 	WalletLedgerRefund = "refund"
@@ -206,6 +210,7 @@ type FulfillmentOrder struct {
 	Amount                int64      `gorm:"not null" json:"amount"`
 	Currency              string     `gorm:"size:12;not null;default:POINT" json:"currency"`
 	OrderStatus           string     `gorm:"size:16;not null;default:paid;index" json:"order_status"`
+	OrderSource           string     `gorm:"size:16;not null;default:api;index" json:"order_source"`
 	BuyerReference        string     `gorm:"size:128" json:"buyer_reference"`
 	RequestFingerprint    string     `gorm:"size:64;not null;default:'';index" json:"-"`
 	RequestData           string     `gorm:"type:text" json:"request_data"`