fix: remove duplicate user_manager instance and reset traffic counters after report

- Remove second user_manager creation via serviceManager.Create to prevent
  double-counting (both instances tracked the same connections)
- Reset per-user atomic counters after each successful traffic report so
  the control panel receives independent per-interval deltas instead of
  unbounded cumulative values

box.go

@@ -441,18 +441,6 @@ func New(options Options) (*Box, error) {
 			service.MustRegister[adapter.V2RayServer](ctx, v2rayServer)
 		}
 	}
-	if experimentalOptions.UserManager != nil {
-		err = serviceManager.Create(
-			ctx,
-			logFactory.NewLogger("service/user_manager"),
-			"user_manager",
-			C.TypeUserManager,
-			experimentalOptions.UserManager,
-		)
-		if err != nil {
-			return nil, E.Cause(err, "create user_manager")
-		}
-	}
 	if ntpOptions.Enabled {
 		ntpDialer, err := dialer.New(ctx, ntpOptions.DialerOptions, ntpOptions.ServerIsDomain())
 		if err != nil {

service/usermanager/manager.go

@@ -576,6 +576,20 @@ func (m *Manager) reportTrafficToServer() {
 	}
 	resp.Body.Close()
 	m.logger.Debug("traffic reported, users=", len(traffic))
+
+	// Reset counters after successful report so the next report only
+	// contains fresh traffic (delta since last report).
+	// This avoids overcounting when multiple nodes or user_manager
+	// instances report for the same user — the control panel always
+	// receives independent per-interval values.
+	m.trafficAccess.Lock()
+	for username := range traffic {
+		if stored, ok := m.traffic[username]; ok {
+			stored.Tx.Add(-traffic[username].Tx)
+			stored.Rx.Add(-traffic[username].Rx)
+		}
+	}
+	m.trafficAccess.Unlock()
 }
 
 // HTTP API