feat: 用户订阅显示节点分组名及限速起止时间

- UserSubscribe/UserSubscribeDetail 新增 node_group_id/node_group_name 字段
- 管理员查询用户订阅列表批量填充分组名
- 管理员查询单个订阅详情填充分组名
- ThrottleResult/UserSubscribeDetail 新增 throttle_start/throttle_end 字段
- 限速时返回限速窗口起止时间（秒级 Unix 时间戳）

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

internal/logic/admin/user/getUserSubscribeByIdLogic.go

@@ -3,6 +3,7 @@ package user
 import (
 	"context"
 
+	"github.com/perfect-panel/server/internal/model/group"
 	"github.com/perfect-panel/server/internal/svc"
 	"github.com/perfect-panel/server/internal/types"
 	"github.com/perfect-panel/server/pkg/logger"
@@ -36,12 +37,22 @@ func (l *GetUserSubscribeByIdLogic) GetUserSubscribeById(req *types.GetUserSubsc
 	var subscribeDetails types.UserSubscribeDetail
 	tool.DeepCopy(&subscribeDetails, sub)
 
+	// 填充分组名
+	if sub.NodeGroupId > 0 {
+		var ng group.NodeGroup
+		if err := l.svcCtx.DB.WithContext(l.ctx).First(&ng, sub.NodeGroupId).Error; err == nil {
+			subscribeDetails.NodeGroupName = ng.Name
+		}
+	}
+
 	// Calculate speed limit status
 	if sub.Subscribe != nil && sub.Status == 1 {
 		result := speedlimit.Calculate(l.ctx, l.svcCtx.DB, sub.UserId, sub.Id, sub.Subscribe.SpeedLimit, sub.Subscribe.TrafficLimit)
 		subscribeDetails.EffectiveSpeed = result.EffectiveSpeed
 		subscribeDetails.IsThrottled = result.IsThrottled
 		subscribeDetails.ThrottleRule = result.ThrottleRule
+		subscribeDetails.ThrottleStart = result.ThrottleStart
+		subscribeDetails.ThrottleEnd = result.ThrottleEnd
 	}
 
 	return &subscribeDetails, nil