Reloadable configuration, FontService (WIP)

src/GuiApp/Avalonia/FileTime.GuiApp/ViewModels/MainWindowLoadingViewModel.cs

@@ -1,6 +1,9 @@
+using System.Reactive.Subjects;
+
 namespace FileTime.GuiApp.ViewModels;
 
 public class MainWindowLoadingViewModel : IMainWindowViewModelBase
 {
     public bool Loading => true;
+    public IObservable<string?> MainFont { get; } = new BehaviorSubject<string?>("");
 }