Add VPN session monitoring service

lib/services/vpn_session_monitor.dart

@@ -0,0 +1,26 @@
+import 'dart:isolate';
+import 'dart:math';
+import 'package:waylume_server/services/vpn_session_service.dart';
+
+void initVpnSessionMonitor() {
+  // Run this on a separate thread
+  Isolate.spawn((_) async {
+    
+    // To avoid server deadlock, add random delay
+    await Future.delayed(Duration(seconds: Random().nextInt(10)));
+    
+    print('VPN Session Monitor started');
+    
+    while (true) {
+      try {
+        await VpnSessionService.detectSessions();
+      } catch (e) {
+        print('Error in VPN session monitor: $e');
+      }
+      
+      // Check for sessions every 60 seconds
+      await Future.delayed(Duration(seconds: 60));
+    }
+    
+  }, null);
+}