fix: 单订阅模式下避免重复创建订阅

1. FindSingleModeAnchorSubscribe 补充 status=4（流量耗完）到查询范围，
   避免流量耗尽的订阅被忽略导致续费时新建订阅

2. activateOrderLogic NewPurchase 路径去掉套餐ID匹配检查，
   单订阅模式下无论购买何种套餐都更新现有订阅而非新建

3. singleModeHelper fallback 查询同步补充 status=4

Co-Authored-By: claude-flow <ruv@ruv.net>

internal/logic/public/iap/apple/singleModeHelper.go

@@ -22,7 +22,7 @@ func findSingleModeMergeTarget(ctx context.Context, svcCtx *svc.ServiceContext,
 		return nil, err
 	}
 
-	userSubs, queryErr := svcCtx.UserModel.QueryUserSubscribe(ctx, userId, 0, 1, 2, 3, 5)
+	userSubs, queryErr := svcCtx.UserModel.QueryUserSubscribe(ctx, userId, 0, 1, 2, 3, 4, 5)
 	if queryErr != nil {
 		return nil, queryErr
 	}