fix: enhance WebSocket stability, resolve XHTTP configurations and fix UI loading shifts (#3997)

* feat: implement real-time traffic monitoring and UI updates using a high-performance WebSocket hub and background job system

* feat: add bulk client management support and improve inbound data handling

* Fix bug

* **Fixes & Changes:**
1. **Fixed XPadding Placement Dropdown**:
   - Added the missing `cookie` and `query` options to `xPaddingPlacement` (`stream_xhttp.html`).
   - *Why:* Previously, users wanting `cookie` obfuscation were forced to use the `header` placement string. This caused Xray-core to blindly intercept the entire monolithic HTTP Cookie header, failing internal padding-length validations and causing the inbound to silently drop the connection.
2. **Fixed Uplink Data Placement Validation**:
   - Replaced the unsupported `query` option with `cookie` in `uplinkDataPlacement`.
   - *Why:* Xray-core's `transport_internet.go` explicitly forbids `query` as an uplink placement option. Selecting it from the UI previously sent a payload that would cause Xray-core to instantly throw an `unsupported uplink data placement: query` panic. Adding `cookie` perfectly aligns the UI with Xray-core restrictions.
### Related Issues
- Resolves #3992

* This commit fixes structural payload issues preventing XHTTP from functioning correctly and eliminates WebSocket log spam.
- **[Fix X-Padding UI]** Added missing `cookie` and `query` options to X-Padding Placement. Fixes the issue where using Cookie fallback triggers whole HTTP Cookie header interception and silent drop in Xray-core. (Resolves [#3992](https://github.com/MHSanaei/3x-ui/issues/3992))
- **[Fix Uplink Data Options]** Replaced the invalid `query` option with `cookie` in Uplink Data Placement dropdown to prevent Xray-core backend panic `unsupported uplink data placement: query`.
- **[Fix WebSockets Spam]** Boosted `maxMessageSize` boundary to 100MB and gracefully handled fallback fetch signals via `broadcastInvalidate` to avoid buffer dropping spam. (Resolves [#3984](https://github.com/MHSanaei/3x-ui/issues/3984))

* Fix

* gofmt

* fix(websocket): resolve channel race condition and graceful shutdown deadlock

* Fix: inbounds switch

* Change max quantity from 10000 to 500

* fix

1 files changed, 19 insertions, 13 deletions

diff --git a/web/job/xray_traffic_job.go b/web/job/xray_traffic_job.go
index 8d2bfbd6..f443aa77 100644
--- a/web/job/xray_traffic_job.go
+++ b/web/job/xray_traffic_job.go
@@ -50,7 +50,13 @@ func (j *XrayTrafficJob) Run() {
 		j.xrayService.SetToNeedRestart()
 	}
 
-	// Get online clients and last online map for real-time status updates
+	// If no frontend client is connected, skip all WebSocket broadcasting routines,
+	// including expensive DB queries for online clients and JSON marshaling.
+	if !websocket.HasClients() {
+		return
+	}
+
+	// Update online clients list and map
 	onlineClients := j.inboundService.GetOnlineClients()
 	lastOnlineMap, err := j.inboundService.GetClientsLastOnline()
 	if err != nil {
@@ -58,8 +64,17 @@ func (j *XrayTrafficJob) Run() {
 		lastOnlineMap = make(map[string]int64)
 	}
 
+	// Broadcast traffic update (deltas and online stats) via WebSocket
+	trafficUpdate := map[string]any{
+		"traffics":       traffics,
+		"clientTraffics": clientTraffics,
+		"onlineClients":  onlineClients,
+		"lastOnlineMap":  lastOnlineMap,
+	}
+	websocket.BroadcastTraffic(trafficUpdate)
+
 	// Fetch updated inbounds from database with accumulated traffic values
-	// This ensures frontend receives the actual total traffic, not just delta values
+	// This ensures frontend receives the actual total traffic for real-time UI refresh.
 	updatedInbounds, err := j.inboundService.GetAllInbounds()
 	if err != nil {
 		logger.Warning("get all inbounds for websocket failed:", err)
@@ -70,16 +85,8 @@ func (j *XrayTrafficJob) Run() {
 		logger.Warning("get all outbounds for websocket failed:", err)
 	}
 
-	// Broadcast traffic update via WebSocket with accumulated values from database
-	trafficUpdate := map[string]any{
-		"traffics":       traffics,
-		"clientTraffics": clientTraffics,
-		"onlineClients":  onlineClients,
-		"lastOnlineMap":  lastOnlineMap,
-	}
-	websocket.BroadcastTraffic(trafficUpdate)
-
-	// Broadcast full inbounds update for real-time UI refresh
+	// The WebSocket hub will automatically check the payload size.
+	// If it exceeds 100MB, it sends a lightweight 'invalidate' signal instead.
 	if updatedInbounds != nil {
 		websocket.BroadcastInbounds(updatedInbounds)
 	}
@@ -87,7 +94,6 @@ func (j *XrayTrafficJob) Run() {
 	if updatedOutbounds != nil {
 		websocket.BroadcastOutbounds(updatedOutbounds)
 	}
-
 }
 
 func (j *XrayTrafficJob) informTrafficToExternalAPI(inboundTraffics []*xray.Traffic, clientTraffics []*xray.ClientTraffic) {