Back navigation and shell improvements.

Wino.Mail.WinUI/Views/SettingsPage.xaml.cs

@@ -77,9 +77,6 @@ public sealed partial class SettingsPage : SettingsPageAbstract,
         // Unregister frame navigation event
         SettingsFrame.Navigated -= SettingsFrameNavigated;
 
-        // Reset navigation state when leaving SettingsPage
-        ViewModel.StatePersistenceService.HasCurrentModeBackStack = false;
-
         base.OnNavigatingFrom(e);
     }
 
@@ -225,9 +222,11 @@ public sealed partial class SettingsPage : SettingsPageAbstract,
 
     private void UpdateBackNavigationState()
     {
-        ViewModel.StatePersistenceService.HasCurrentModeBackStack = PageHistory.Count > 1 && SettingsFrame.CanGoBack;
+        WeakReferenceMessenger.Default.Send(new TitleBarShellContentUpdated());
     }
 
+    public bool CanNavigateBack => PageHistory.Count > 1 && SettingsFrame.CanGoBack;
+
     private async Task RefreshCurrentPageStateAsync()
     {
         var activePage = PageHistory.LastOrDefault()?.Request.PageType ?? WinoPage.SettingOptionsPage;

Wino.Mail.WinUI/Views/WinoAppShell.xaml.cs

@@ -157,7 +157,6 @@ public sealed partial class WinoAppShell : Views.Abstract.WinoAppShellAbstract,
 
     private void ResetShellModeNavigationState()
     {
-        ViewModel.StatePersistenceService.HasCurrentModeBackStack = false;
         InnerShellFrame.BackStack.Clear();
         InnerShellFrame.ForwardStack.Clear();
     }