Rotate to another server on stuck proxy connection

- ProxyRotationController now probes VLESS+Reality servers with a real TCP
  latency check (the MTProto check always failed for them), so rotation can
  actually find a working server
- Switching to a built-in VLESS server now starts Xray and points Telegram
  at the local SOCKS5 listener via XrayController.switchToBuiltinProxy,
  instead of pointing at the raw server address
- Skip built-in servers that don't match the current network when rotating
- Trigger rotation not only on ConnectingToProxy but also on prolonged
  Connecting/WaitingForNetwork states, covering the infinite-connecting case

TMessagesProj/src/main/java/org/telegram/messenger/ProxyRotationController.java

@@ -31,6 +31,28 @@ public class ProxyRotationController implements NotificationCenter.NotificationC
             }
             startedCheck = true;
             proxyInfo.checking = true;
+            if (proxyInfo.isVless()) {
+                // VLESS+Reality servers don't speak the MTProto proxy protocol,
+                // so Telegram's checkProxy always fails. Use a real TCP-connect
+                // latency probe to the server endpoint instead.
+                final SharedConfig.ProxyInfo info = proxyInfo;
+                new Thread(() -> {
+                    long latency = XrayController.measureTcpLatency(info.address, info.port, 4000);
+                    AndroidUtilities.runOnUIThread(() -> {
+                        info.availableCheckTime = SystemClock.elapsedRealtime();
+                        info.checking = false;
+                        if (latency < 0) {
+                            info.available = false;
+                            info.ping = 0;
+                        } else {
+                            info.ping = latency;
+                            info.available = true;
+                        }
+                        NotificationCenter.getGlobalInstance().postNotificationName(NotificationCenter.proxyCheckDone, info);
+                    });
+                }, "vless-rotation-ping").start();
+                continue;
+            }
             proxyInfo.proxyCheckPingId = ConnectionsManager.getInstance(currentAccount).checkProxy(proxyInfo.address, proxyInfo.port, proxyInfo.username, proxyInfo.password, proxyInfo.secret, time -> AndroidUtilities.runOnUIThread(() -> {
                 proxyInfo.availableCheckTime = SystemClock.elapsedRealtime();
                 proxyInfo.checking = false;
@@ -69,6 +91,22 @@ public class ProxyRotationController implements NotificationCenter.NotificationC
             if (info == SharedConfig.currentProxy || info.checking || !info.available) {
                 continue;
             }
+            // Don't switch to a built-in server that doesn't match the current
+            // network (e.g. a Wi-Fi server while we're on mobile data).
+            if (info.builtin && !XrayController.matchesCurrentNetwork(info)) {
+                continue;
+            }
+
+            if (info.builtin && info.isVless()) {
+                // Built-in VLESS proxy: start Xray and point Telegram at the
+                // local SOCKS5 listener. switchToBuiltinProxy persists the
+                // selection and applies the proxy settings itself.
+                SharedConfig.currentProxy = info;
+                XrayController.switchToBuiltinProxy(info);
+                NotificationCenter.getGlobalInstance().postNotificationName(NotificationCenter.proxySettingsChanged);
+                NotificationCenter.getGlobalInstance().postNotificationName(NotificationCenter.proxyChangedByRotation);
+                break;
+            }
 
             SharedPreferences.Editor editor = MessagesController.getGlobalMainSettings().edit();
             editor.putString("proxy_ip", info.address);
@@ -116,7 +154,13 @@ public class ProxyRotationController implements NotificationCenter.NotificationC
 
             int state = ConnectionsManager.getInstance(account).getConnectionState();
 
-            if (state == ConnectionsManager.ConnectionStateConnectingToProxy) {
+            // Treat any prolonged "not connected" state as a stuck connection
+            // that should trigger a rotation to another server after the
+            // configured timeout. This covers the "infinite connecting" case
+            // where Telegram keeps trying a dead proxy without ever failing.
+            if (state == ConnectionsManager.ConnectionStateConnectingToProxy
+                    || state == ConnectionsManager.ConnectionStateConnecting
+                    || state == ConnectionsManager.ConnectionStateWaitingForNetwork) {
                 if (!isCurrentlyChecking) {
                     AndroidUtilities.runOnUIThread(checkProxyAndSwitchRunnable, ROTATION_TIMEOUTS.get(SharedConfig.proxyRotationTimeout) * 1000L);
                 }

TMessagesProj/src/main/java/org/telegram/messenger/XrayController.java

@@ -118,6 +118,37 @@ public class XrayController {
         }
     }
 
+    /** All built-in proxies that match the current network, in declaration order. */
+    public static java.util.List<SharedConfig.ProxyInfo> builtinProxiesForCurrentNetwork() {
+        java.util.List<SharedConfig.ProxyInfo> list = new java.util.ArrayList<>();
+        for (XrayServers.Server s : XrayServers.SERVERS) {
+            SharedConfig.ProxyInfo p = fromServer(s);
+            if (p != null && matchesCurrentNetwork(p)) list.add(p);
+        }
+        return list;
+    }
+
+    /**
+     * Switch the active built-in proxy: (re)start Xray with the given server,
+     * persist the selection and point Telegram at the local SOCKS5 listener.
+     * Runs the heavy work on a background thread. Safe to call from any thread.
+     */
+    public static void switchToBuiltinProxy(SharedConfig.ProxyInfo proxy) {
+        if (proxy == null || !proxy.isVless()) return;
+        final VlessConfig cfg = proxy.toVlessConfig();
+        new Thread(() -> {
+            boolean ok = start(cfg);
+            if (ok) {
+                SharedConfig.currentProxy = proxy;
+                persistBuiltinProxySelection(proxy);
+                try { Thread.sleep(300); } catch (InterruptedException ignored) {}
+                ConnectionsManager.setProxySettings(true, "127.0.0.1", cfg.localPort, "", "", "");
+            } else {
+                Log.e(TAG, "switchToBuiltinProxy: Xray failed to start for " + proxy.builtinName);
+            }
+        }, "xray-switch").start();
+    }
+
     private static SharedConfig.ProxyInfo fromServer(XrayServers.Server s) {
         if (s == null || s.address == null || s.address.isEmpty()) return null;
         SharedConfig.ProxyInfo p = SharedConfig.ProxyInfo.createVless(