fix: 流量触发限速后主动清除节点用户缓存

节点用户列表缓存(server:user:{id})永不过期，用户流量超限触发按量限速后
缓存中仍是旧的速度值，节点不会感知限速状态。

修复：每次写入 traffic_log 后，检查该订阅是否触发按量限速规则，
若 IsThrottled=true 则立即删除对应节点的用户列表缓存，
节点下次拉取时重新计算并应用降速后的 speed_limit。

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

queue/logic/traffic/trafficStatisticsLogic.go

@@ -3,11 +3,13 @@ package traffic
 import (
 	"context"
 	"encoding/json"
+	"fmt"
 	"strings"
 	"time"
 
 	"github.com/perfect-panel/server/internal/model/node"
 	"github.com/perfect-panel/server/pkg/logger"
+	"github.com/perfect-panel/server/pkg/speedlimit"
 
 	"github.com/hibiken/asynq"
 	"github.com/perfect-panel/server/internal/model/traffic"
@@ -126,6 +128,21 @@ func (l *TrafficStatisticsLogic) ProcessTask(ctx context.Context, task *asynq.Ta
 				logger.Field("error", err.Error()),
 			)
 		}
+
+		// 写完流量后检查是否触发按量限速，若触发则清除节点缓存使限速立即生效
+		if planSub, planErr := l.svc.SubscribeModel.FindOne(ctx, sub.SubscribeId); planErr == nil &&
+			(planSub.SpeedLimit > 0 || planSub.TrafficLimit != "") {
+			throttle := speedlimit.Calculate(ctx, l.svc.DB, sub.UserId, sub.Id, planSub.SpeedLimit, planSub.TrafficLimit)
+			if throttle.IsThrottled {
+				cacheKey := fmt.Sprintf("%s%d", node.ServerUserListCacheKey, payload.ServerId)
+				if delErr := l.svc.Redis.Del(ctx, cacheKey).Err(); delErr != nil {
+					logger.WithContext(ctx).Error("[TrafficStatistics] Clear server user cache failed",
+						logger.Field("serverId", payload.ServerId),
+						logger.Field("error", delErr.Error()),
+					)
+				}
+			}
+		}
 	}
 	return nil
 }