feat(vpn): pre-compile session retry backoff regex, track and display warning in connection status card dynamically during connecting phase

Author: Hidden-Node

android/app/src/main/java/com/masterdns/vpn/ui/home/HomeScreen.kt

@@ -71,6 +71,7 @@ fun HomeScreen(
     val scanStatus by VpnManager.scanStatus.collectAsState()
     val selectedProfile by viewModel.selectedProfile.collectAsState()
     val error by VpnManager.errorMessage.collectAsState()
+    val connectionWarning by VpnManager.connectionWarning.collectAsState()
     val context = LocalContext.current
 
     val advanced = remember(selectedProfile?.advancedJson) {
@@ -239,7 +240,8 @@ fun HomeScreen(
                             socksAuthEnabled = socksAuthEnabled,
                             socksUser = socksUser,
                             socksPass = socksPass,
-                            isConnecting = isConnecting
+                            isConnecting = isConnecting,
+                            connectionWarning = connectionWarning
                         )
                         Spacer(modifier = Modifier.height(MdvSpace.S3))
                         MdvProfileSelectorCard(
@@ -311,7 +313,8 @@ fun HomeScreen(
                     socksAuthEnabled = socksAuthEnabled,
                     socksUser = socksUser,
                     socksPass = socksPass,
-                    isConnecting = isConnecting
+                    isConnecting = isConnecting,
+                    connectionWarning = connectionWarning
                 )
 
                 Spacer(modifier = Modifier.height(MdvSpace.S3))

android/app/src/main/java/com/masterdns/vpn/ui/home/HomeStatusCards.kt

@@ -45,7 +45,8 @@ fun MdvConnectionTelemetryCard(
     socksAuthEnabled: Boolean,
     socksUser: String,
     socksPass: String,
-    isConnecting: Boolean
+    isConnecting: Boolean,
+    connectionWarning: String? = null
 ) {
     MdvCardLow(modifier = Modifier.fillMaxWidth()) {
         Column(
@@ -186,6 +187,35 @@ fun MdvConnectionTelemetryCard(
                 }
             }
 
+            // Connection Warning Section
+            if (connectionWarning != null && vpnState == VpnManager.VpnState.CONNECTING) {
+                androidx.compose.foundation.layout.Spacer(modifier = Modifier.height(MdvSpace.S3))
+                androidx.compose.material3.Surface(
+                    shape = androidx.compose.foundation.shape.RoundedCornerShape(12.dp),
+                    color = ConnectingAmber.copy(alpha = 0.12f),
+                    border = androidx.compose.foundation.BorderStroke(1.dp, ConnectingAmber.copy(alpha = 0.4f)),
+                    modifier = Modifier.fillMaxWidth()
+                ) {
+                    Row(
+                        modifier = Modifier.padding(horizontal = MdvSpace.S3, vertical = 10.dp),
+                        verticalAlignment = Alignment.CenterVertically
+                    ) {
+                        Text(
+                            text = "⚠",
+                            style = MaterialTheme.typography.titleMedium,
+                            color = ConnectingAmber,
+                            modifier = Modifier.padding(end = 8.dp)
+                        )
+                        Text(
+                            text = connectionWarning,
+                            style = MaterialTheme.typography.bodySmall,
+                            color = ConnectingAmber,
+                            fontWeight = FontWeight.SemiBold
+                        )
+                    }
+                }
+            }
+
             // Network Traffic Grid
             if (downloadTotalBytes > 0 || uploadTotalBytes > 0 || downBps > 0 || upBps > 0) {
                 androidx.compose.foundation.layout.Spacer(modifier = Modifier.height(MdvSpace.S3))

android/app/src/main/java/com/masterdns/vpn/util/VpnManager.kt

@@ -56,6 +56,9 @@ object VpnManager {
     private val _errorMessage = MutableStateFlow<String?>(null)
     val errorMessage: StateFlow<String?> = _errorMessage.asStateFlow()
 
+    private val _connectionWarning = MutableStateFlow<String?>(null)
+    val connectionWarning: StateFlow<String?> = _connectionWarning.asStateFlow()
+
     private val _activeResolvers = MutableStateFlow<List<String>>(emptyList())
     val activeResolvers: StateFlow<List<String>> = _activeResolvers.asStateFlow()
 
@@ -130,6 +133,10 @@ object VpnManager {
         "DNS Resolver disabled.*?(\\d+\\.\\d+\\.\\d+\\.\\d+:\\d+|\\[[a-fA-F0-9:]+\\]:\\d+)",
         RegexOption.IGNORE_CASE
     )
+    private val SESSION_INIT_BACKOFF_REGEX = Regex(
+        "Session init retry backoff:\\s*(.*)",
+        RegexOption.IGNORE_CASE
+    )
     private val TIMESTAMP_CANDIDATES = listOf(
         TimestampCandidate(
             Regex("^(\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}\\.\\d{3}Z)(.*)$"),
@@ -170,6 +177,10 @@ object VpnManager {
             _connectedDurationSeconds.value = 0L
             _uploadTotalBytes.value = 0L
             _downloadTotalBytes.value = 0L
+            _connectionWarning.value = null
+        }
+        if (newState == VpnState.CONNECTED || newState == VpnState.DISCONNECTED || newState == VpnState.ERROR) {
+            _connectionWarning.value = null
         }
         if (newState == VpnState.CONNECTED) {
             _scanStatus.value = _scanStatus.value.copy(
@@ -427,6 +438,11 @@ object VpnManager {
         ) {
             _scanStatus.value = _scanStatus.value.copy(scanning = false)
         }
+
+        SESSION_INIT_BACKOFF_REGEX.find(line)?.let { match ->
+            val backoff = match.groupValues[1].trim()
+            _connectionWarning.value = "Session init retry backoff: $backoff"
+        }
     }
 
     private fun normalizeLogTimestampToLocal(line: String): String {