新功能(#69): 用户级限速覆盖 — 数据层 + 核心逻辑 + 管理接口

- 新增 migration 02153: user_subscribe 表添加 speed_limit、traffic_limit 列（幂等）
- model 层 Subscribe/SubscribeDetails 新增用户级限速字段（*string 类型支持 nil 回退）
- server 用户列表和管理员详情接口支持用户级限速覆盖优先级计算
- 更新管理员订阅更新接口支持写入/清除用户级限速

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

internal/logic/admin/user/getUserSubscribeByIdLogic.go

@@ -2,6 +2,7 @@ package user
 
 import (
 	"context"
+	"encoding/json"
 
 	"github.com/perfect-panel/server/internal/model/group"
 	"github.com/perfect-panel/server/internal/svc"
@@ -36,6 +37,13 @@ func (l *GetUserSubscribeByIdLogic) GetUserSubscribeById(req *types.GetUserSubsc
 	}
 	var subscribeDetails types.UserSubscribeDetail
 	tool.DeepCopy(&subscribeDetails, sub)
+	subscribeDetails.SpeedLimit = sub.SpeedLimit
+	if sub.TrafficLimit != nil && *sub.TrafficLimit != "" {
+		_ = json.Unmarshal([]byte(*sub.TrafficLimit), &subscribeDetails.TrafficLimit)
+	}
+	if sub.Subscribe != nil {
+		subscribeDetails.PlanSpeedLimit = sub.Subscribe.SpeedLimit
+	}
 
 	// 填充分组名
 	if sub.NodeGroupId > 0 {
@@ -47,7 +55,17 @@ func (l *GetUserSubscribeByIdLogic) GetUserSubscribeById(req *types.GetUserSubsc
 
 	// 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)
+		baseSpeed := sub.Subscribe.SpeedLimit
+		if sub.SpeedLimit > 0 {
+			baseSpeed = sub.SpeedLimit
+		}
+
+		trafficLimit := sub.Subscribe.TrafficLimit
+		if sub.TrafficLimit != nil && *sub.TrafficLimit != "" {
+			trafficLimit = *sub.TrafficLimit
+		}
+
+		result := speedlimit.Calculate(l.ctx, l.svcCtx.DB, sub.UserId, sub.Id, baseSpeed, trafficLimit)
 		subscribeDetails.EffectiveSpeed = result.EffectiveSpeed
 		subscribeDetails.IsThrottled = result.IsThrottled
 		subscribeDetails.ThrottleRule = result.ThrottleRule

internal/logic/admin/user/updateUserSubscribeLogic.go

@@ -45,7 +45,7 @@ func (l *UpdateUserSubscribeLogic) UpdateUserSubscribe(req *types.UpdateUserSubs
 	}
 	trafficLimit := userSub.TrafficLimit
 	if req.TrafficLimit != nil {
-		trafficLimit = *req.TrafficLimit
+		trafficLimit = req.TrafficLimit
 	}
 
 	err = l.svcCtx.UserModel.UpdateSubscribe(l.ctx, &user.Subscribe{