fix: gamescope crash due to gsettings probe

Author: benaclejames

VRCFaceTracking/App.axaml

@@ -22,6 +22,6 @@
     </Application.Resources>
 
     <Application.Styles>
-        <sty:FluentAvaloniaTheme PreferSystemTheme="True" PreferUserAccentColor="True" />
+        <sty:FluentAvaloniaTheme PreferSystemTheme="False" PreferUserAccentColor="True" />
     </Application.Styles>
 </Application>

VRCFaceTracking/App.axaml.cs

@@ -4,6 +4,7 @@
 using Microsoft.Extensions.Logging;
 using Avalonia.Data.Core.Plugins;
 using CommunityToolkit.Mvvm.DependencyInjection;
+using FluentAvalonia.Styling;
 using Microsoft.Extensions.Hosting;
 using VRCFaceTracking.Contracts.Services;
 using VRCFaceTracking.Views;
@@ -21,6 +22,14 @@ public override void Initialize()
         {
             AvaloniaXamlLoader.Load(this);
 
+            // gsettings breaks gamescope on linux and system theme is unreliable on plasma anyways
+            if (!OperatingSystem.IsLinux())
+            {
+                var faTheme = Styles.OfType<FluentAvaloniaTheme>().FirstOrDefault();
+                if (faTheme is not null)
+                    faTheme.PreferSystemTheme = true;
+            }
+
 #if DEBUG
             var loggerFactory = LoggerFactory.Create(b => b
                 .SetMinimumLevel(LogLevel.Information)