新功能(#77): 套餐列表返回促销信息

- 新增 SubscribePromo 响应结构，套餐列表每项追加 promo 字段
- 新增 promo.go 促销候选规则查询与资格评估逻辑
- 重构 authMiddleware 提取 authenticateRequest，新增 OptionalAuthMiddleware
- /v1/public/subscribe/list 改为可选鉴权，未登录仅展示 campaign 类型促销
- /node/list、/group/list 保持强制鉴权不变
- 每个规格只返回最高优先级命中的规则，promo_price 为单价，expires_at 为秒级时间戳
- 新增单测覆盖 campaign/new_user 命中、活动窗口判定等场景

Co-authored-by: multica-agent <github@multica.ai>

internal/logic/public/subscribe/querySubscribeListLogic.go

@@ -47,9 +47,11 @@ func (l *QuerySubscribeListLogic) QuerySubscribeList(req *types.QuerySubscribeLi
 		Total: total,
 	}
 	list := make([]types.Subscribe, len(data))
+	subscribeIDs := make([]int64, 0, len(data))
 	for i, item := range data {
 		var sub types.Subscribe
 		tool.DeepCopy(&sub, item)
+		subscribeIDs = append(subscribeIDs, sub.Id)
 		if item.Discount != "" {
 			var discount []types.SubscribeDiscount
 			_ = json.Unmarshal([]byte(item.Discount), &discount)
@@ -69,6 +71,15 @@ func (l *QuerySubscribeListLogic) QuerySubscribeList(req *types.QuerySubscribeLi
 		}
 	}
 
+	promos, err := loadSubscribePromoMap(l.ctx, l.svcCtx, subscribeIDs)
+	if err != nil {
+		l.Errorw("[QuerySubscribeListLogic] Query Promo Error", logger.Field("error", err.Error()))
+		return nil, err
+	}
+	for i := range list {
+		list[i].Promo = promos[list[i].Id]
+	}
+
 	resp.List = list
 	resp.Total = int64(len(list))
 	return