fix: HashPay 支付跳转到外部支付页面

frontend/src/views/user/Cart.vue

@@ -623,7 +623,7 @@ async function handleCheckout() {
     await cartStore.fetchCart()
     const orderId = res.data?.id
     const selectedChannel = paymentChannels.value.find(ch => ch.code === selectedPayment.value)
-    if (selectedChannel?.type === 'bepusdt' && orderId) {
+    if ((selectedChannel?.type === 'bepusdt' || selectedChannel?.type === 'hashpay') && orderId) {
       router.push(`/checkout/${orderId}`)
     } else {
       router.push('/orders')

frontend/src/views/user/Checkout.vue

@@ -102,6 +102,13 @@ async function createPayment() {
     orderId.value = Number(route.params.id)
     const res: any = await orderApi.createPayment(orderId.value)
     paymentInfo.value = res.data
+
+    // HashPay: 直接跳转到外部支付页面
+    if (res.data.checkout_url) {
+      window.location.href = res.data.checkout_url
+      return
+    }
+
     totalTime.value = res.data.expiration_time || 600
     remaining.value = totalTime.value