fix(billing): 复用待支付套餐订单

frontend/src/api/billing.ts

@@ -126,6 +126,7 @@ export interface BillingCheckoutResponse {
     product?: BillingPlan | null
   }
   payment_instructions: Record<string, unknown>
+  reused_pending_order?: boolean
 }
 
 export interface UserPlanEntitlement {

frontend/src/views/user/BillingPlans.vue

@@ -351,7 +351,11 @@ async function checkoutPlan(plan: BillingPlan) {
       payment_channel: option.payment_channel,
     })
     latestCheckout.value = response
-    success('套餐订单已创建')
+    success(
+      response.reused_pending_order
+        ? '已有待支付订单，已打开原支付链接'
+        : '套餐订单已创建'
+    )
     submitPaymentInstructions(response.payment_instructions)
   } catch (err) {
     log.error('创建套餐订单失败:', err)