fix(online): refresh online-clients list even when no WS frontend is connected (#4515)

XrayTrafficJob and NodeTrafficSyncJob both gated the entire
post-traffic-write block behind websocket.HasClients() to skip
expensive broadcasts when no browser is open. The block included the
RefreshOnlineClientsFromMap call that keeps the in-memory
p.onlineClients list current.

Several non-WS consumers read that same list:
- Telegram bot (tgbot.go calls p.GetOnlineClients in 3 places)
- REST GET /panel/api/onlines (returned to API callers)
- Internal alerts that check whether a client is online

When no browser was watching the dashboard, the list went stale and
stayed empty, so the bot reported "nobody online" and the onlines API
returned [] even when xray had active sessions.

Move RefreshOnlineClientsFromMap above the HasClients guard so the
in-memory list is always fresh. Only the actual BroadcastTraffic /
BroadcastClientStats / BroadcastOutbounds calls (and the
GetAllClientTraffics / GetInboundsTrafficSummary work that feeds them)
remain gated by HasClients.

Closes #4515

web/job/node_traffic_sync_job.go

@@ -101,10 +101,6 @@ func (j *NodeTrafficSyncJob) Run() {
 		j.structural.set()
 	}
 
-	if !websocket.HasClients() {
-		return
-	}
-
 	lastOnline, err := j.inboundService.GetClientsLastOnline()
 	if err != nil {
 		logger.Warning("node traffic sync: get last-online failed:", err)
@@ -115,6 +111,10 @@ func (j *NodeTrafficSyncJob) Run() {
 
 	j.inboundService.RefreshOnlineClientsFromMap(lastOnline)
 
+	if !websocket.HasClients() {
+		return
+	}
+
 	online := j.inboundService.GetOnlineClients()
 	if online == nil {
 		online = []string{}

web/job/xray_traffic_job.go

@@ -65,18 +65,6 @@ func (j *XrayTrafficJob) Run() {
 		j.xrayService.SetToNeedRestart()
 	}
 
-	// If no frontend client is connected, skip all WebSocket broadcasting
-	// routines — including the active-client DB query and JSON marshaling.
-	if !websocket.HasClients() {
-		return
-	}
-
-	// Online presence + traffic deltas — small payload, always fits in WS.
-	// Force non-nil slice/map so JSON marshalling produces [] / {} instead of
-	// `null` when everyone is offline. The frontend's traffic handler treats
-	// a missing/null onlineClients field as "no update", so without this the
-	// "everyone went offline" transition was silently dropped — stale online
-	// users lingered in the list and the online filter kept showing them.
 	lastOnlineMap, err := j.inboundService.GetClientsLastOnline()
 	if err != nil {
 		logger.Warning("get clients last online failed:", err)
@@ -84,13 +72,12 @@ func (j *XrayTrafficJob) Run() {
 	if lastOnlineMap == nil {
 		lastOnlineMap = make(map[string]int64)
 	}
-
-	// Determine online clients from lastOnline timestamps with a 5-second
-	// grace period instead of just the current 5-second traffic poll. This
-	// prevents idle-but-connected clients from randomly disappearing from
-	// the UI between polling windows.
 	j.inboundService.RefreshOnlineClientsFromMap(lastOnlineMap)
 
+	if !websocket.HasClients() {
+		return
+	}
+
 	onlineClients := j.inboundService.GetOnlineClients()
 	if onlineClients == nil {
 		onlineClients = []string{}
@@ -102,11 +89,6 @@ func (j *XrayTrafficJob) Run() {
 		"lastOnlineMap":  lastOnlineMap,
 	})
 
-	// Full snapshot every cycle: absolute per-client counters and inbound
-	// totals. Frontend overwrites both in place. The previous delta path
-	// (activeEmails -> GetActiveClientTraffics) silently omitted the
-	// clients array whenever nobody moved bytes in the cycle, leaving the
-	// client rows in the UI stuck at stale traffic/remained/all-time.
 	clientStatsPayload := map[string]any{}
 	if stats, err := j.inboundService.GetAllClientTraffics(); err != nil {
 		logger.Warning("get all client traffics for websocket failed:", err)
@@ -122,8 +104,6 @@ func (j *XrayTrafficJob) Run() {
 		websocket.BroadcastClientStats(clientStatsPayload)
 	}
 
-	// Outbounds list is small (one row per outbound, no per-client expansion)
-	// so the full snapshot still fits comfortably in WS.
 	if updatedOutbounds, err := j.outboundService.GetOutboundsTraffic(); err == nil && updatedOutbounds != nil {
 		websocket.BroadcastOutbounds(updatedOutbounds)
 	} else if err != nil {