fix: 新购订单自动计算到期时间

src/views/order/OrderList.vue

@@ -1405,6 +1405,19 @@ const handleDurationChange = (value) => {
   orderForm.pay_num = duration
 }
 
+const calculateExpireTime = (months) => {
+  const duration = Math.max(1, Math.floor(Number(months) || 1))
+  const expireDate = new Date()
+  const originalDay = expireDate.getDate()
+
+  expireDate.setDate(1)
+  expireDate.setMonth(expireDate.getMonth() + duration)
+  const lastDay = new Date(expireDate.getFullYear(), expireDate.getMonth() + 1, 0).getDate()
+  expireDate.setDate(Math.min(originalDay, lastDay))
+
+  return expireDate.getTime()
+}
+
 // 分步导航
 const handleNextStep = async () => {
   if (currentStep.value === 0) {
@@ -1420,6 +1433,7 @@ const handleNextStep = async () => {
     if (isAutoPriceMode.value) {
       const priced = await fetchOrderPrice()
       if (!priced) return
+      orderForm.expire_time = calculateExpireTime(orderForm.pay_num)
     }
   }
   currentStep.value++