fix(v2): 订阅激活门改按结算结果(unpaid session 不再无付款激活)

HandleCallback 原门 serr==nil && SubscriptionRef!="" 挡不住 Settle() 对非
PaidSucceeded 事件返回 (SettleIgnored, nil) 的情况(如 Stripe
checkout.session.completed 异步支付 payment_status=unpaid),导致
onSubscriptionActivated 无确认付款先激活订阅。改为按结算结果开门
(SettleProcessed/SettleDuplicate),并在 onSubscriptionActivated 内加
o.Status.Settled() 纵深防御。

internal/gateway/subscription.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"log"
 	"time"
 
 	"github.com/wangjia/pay/internal/model"
@@ -107,6 +108,12 @@ func (g *Gateway) onSubscriptionActivated(ctx context.Context, ev *provider.Paid
 	if err != nil {
 		return err
 	}
+	if !o.Status.Settled() {
+		// 纵深防御:HandleCallback 的门(res==Processed/Duplicate)已挡住未结算订单,
+		// 这里再核一遍订单状态,防止未来调用点绕过门直接调用本函数。
+		log.Printf("[subscription] onSubscriptionActivated 订单未结算 out_trade_no=%s status=%s,拒绝激活", o.OutTradeNo, o.Status)
+		return nil
+	}
 	subID := "SUB-" + att.OutTradeNo // 与 CreateSubscription 同式派生 → 重投算出同一 SubID,Create 幂等
 	created, err := g.subs.Create(&model.Subscription{
 		SubID: subID, OutTradeNo: o.OutTradeNo, BizSystem: o.BizSystem, BizRef: o.BizRef, BizCode: o.BizCode,