Add QrCode authentication

moneymgr_mobile/lib/utils/extensions.dart

@@ -15,18 +15,21 @@ extension BuildContextX on BuildContext {
 
   /// Shows a floating snack bar with text as its content.
   ScaffoldFeatureController<SnackBar, SnackBarClosedReason> showTextSnackBar(
-      String text,
-      ) =>
-      ScaffoldMessenger.of(this).showSnackBar(SnackBar(
-        behavior: SnackBarBehavior.floating,
-        content: Text(text),
-      ));
+    String text, {
+    Duration? duration,
+  }) => ScaffoldMessenger.of(this).showSnackBar(
+    SnackBar(
+      behavior: SnackBarBehavior.floating,
+      content: Text(text),
+      duration: duration ?? Duration(milliseconds: 4000),
+    ),
+  );
 
   void showAppLicensePage() => showLicensePage(
     context: this,
     useRootNavigator: true,
     applicationName: 'MoneyMgr',
-    applicationLegalese: '(c) Pierre HUBERT 2025 - ${DateTime.now().year}'
+    applicationLegalese: '(c) Pierre HUBERT 2025 - ${DateTime.now().year}',
   );
 }