fix: Make transactions atomic / AutoLogout

lib/app/app_lifecycle_lock.dart

@@ -0,0 +1,20 @@
+import 'package:flutter/material.dart';
+
+class AppLifecycleLockObserver extends WidgetsBindingObserver {
+  final VoidCallback onLock;
+
+  AppLifecycleLockObserver({required this.onLock});
+
+  @override
+  void didChangeAppLifecycleState(AppLifecycleState state) {
+    switch (state) {
+      case AppLifecycleState.inactive:
+      case AppLifecycleState.hidden:
+      case AppLifecycleState.paused:
+      case AppLifecycleState.detached:
+        onLock();
+      case AppLifecycleState.resumed:
+        break;
+    }
+  }
+}