Default beta testers to modern UI (#4728)

* Launch modern UI by default for beta testers

When EnableUniGetUIBeta is set, IsClassicModeEnabled() now returns false,
causing the modern Avalonia UI to launch automatically.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Disable classic mode toggle when beta tester setting is enabled

The 'Use classic mode' checkbox is now grayed out (IsEnabled=false) when
EnableUniGetUIBeta is set, since the modern UI is forced for beta testers.
A tooltip explains why the control is disabled.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: mamoreau-devolutions

src/UniGetUI.Avalonia/ViewModels/Pages/SettingsPages/Interface_PViewModel.cs

@@ -5,6 +5,7 @@
 using UniGetUI.Avalonia.ViewModels;
 using UniGetUI.Core.Data;
 using UniGetUI.Core.Logging;
+using UniGetUI.Core.SettingsEngine;
 using UniGetUI.Core.Tools;
 
 namespace UniGetUI.Avalonia.ViewModels.Pages.SettingsPages;
@@ -13,6 +14,12 @@ public partial class Interface_PViewModel : ViewModelBase
 {
     public bool IsWindows { get; } = OperatingSystem.IsWindows();
 
+    /// <summary>
+    /// True when the user is enrolled in the beta program. In that case the modern UI is forced
+    /// and the classic-mode toggle should be disabled.
+    /// </summary>
+    public bool IsBetaTester { get; } = Settings.Get(Settings.K.EnableUniGetUIBeta);
+
     [ObservableProperty] private string _iconCacheSizeText = "";
 
     public event EventHandler? RestartRequired;

src/UniGetUI.Avalonia/Views/Pages/SettingsPages/Interface_P.axaml

@@ -31,6 +31,8 @@
                                    Text="{t:Translate Use classic mode}"
                                    WarningText="{t:Translate Restart UniGetUI to apply this change}"
                                    StateChangedCommand="{Binding ShowRestartRequiredCommand}"
+                                   IsEnabled="{Binding !IsBetaTester}"
+                                   ToolTip.Tip="{t:Translate The classic UI is disabled for beta testers}"
                                    CornerRadius="8"/>
 
              <StackPanel x:Name="SystemTraySection" Orientation="Vertical">

src/UniGetUI.Tests/ModernAppLauncherTests.cs

@@ -37,6 +37,16 @@ public void ClassicModeDefaultsToEnabled()
         Assert.False(ModernAppLauncher.IsClassicModeEnabled());
     }
 
+    [Fact]
+    public void BetaTestersDefaultToModernUI()
+    {
+        Assert.True(ModernAppLauncher.IsClassicModeEnabled());
+
+        Settings.Set(Settings.K.EnableUniGetUIBeta, true);
+
+        Assert.False(ModernAppLauncher.IsClassicModeEnabled());
+    }
+
     [Fact]
     public void ResolveModernExecutablePath_PrefersRootExecutable()
     {

src/UniGetUI/ModernAppLauncher.cs

@@ -9,7 +9,8 @@ internal static class ModernAppLauncher
     internal const string ModernAppDirectoryName = "Avalonia";
     internal const string ModernAppExecutableName = "UniGetUI.Avalonia.exe";
 
-    public static bool IsClassicModeEnabled() => !Settings.Get(Settings.K.DisableClassicMode);
+    public static bool IsClassicModeEnabled() =>
+        !Settings.Get(Settings.K.DisableClassicMode) && !Settings.Get(Settings.K.EnableUniGetUIBeta);
 
     public static void Launch(string[] args)
     {