feat: add more easter eggs

lib/views/settings_view.dart

@@ -15,6 +15,7 @@ import '../utils/navigation.dart';
 import '../viewmodels/admin_pin_view_model.dart';
 import '../viewmodels/pin_lock_view_model.dart';
 import '../viewmodels/settings_view_model.dart';
+import 'credits_view.dart';
 import 'pin_lock_view.dart';
 
 class SettingsScreenView extends StatefulWidget {
@@ -27,6 +28,9 @@ class SettingsScreenView extends StatefulWidget {
 class _SettingsScreenViewState extends State<SettingsScreenView> {
   String _appVersion = '';
   Timer? _versionHoldTimer;
+  static const _versionTapWindow = Duration(milliseconds: 600);
+  int _versionTapCount = 0;
+  DateTime? _lastVersionTap;
 
   @override
   void initState() {
@@ -65,6 +69,25 @@ class _SettingsScreenViewState extends State<SettingsScreenView> {
     _versionHoldTimer = null;
   }
 
+  /// Five quick taps on the version number roll the credits.
+  void _onVersionTap() {
+    final now = DateTime.now();
+    final last = _lastVersionTap;
+    _versionTapCount = last != null && now.difference(last) < _versionTapWindow
+        ? _versionTapCount + 1
+        : 1;
+    _lastVersionTap = now;
+
+    if (_versionTapCount < 5) return;
+    _versionTapCount = 0;
+    Navigator.of(context).push(
+      MaterialPageRoute<void>(
+        fullscreenDialog: true,
+        builder: (_) => CreditsView(appVersion: _appVersion),
+      ),
+    );
+  }
+
   @override
   void dispose() {
     _cancelVersionHold();
@@ -377,6 +400,7 @@ class _SettingsScreenViewState extends State<SettingsScreenView> {
                   onTapDown: (_) => _startVersionHold(),
                   onTapUp: (_) => _cancelVersionHold(),
                   onTapCancel: _cancelVersionHold,
+                  onTap: _onVersionTap,
                   child: Center(
                     child: Text(
                       l10n.version(_appVersion),