Recursive container size scan

src/GuiApp/FileTime.Avalonia/ViewModels/ItemPreview/ISizeItemViewModel.cs

@@ -0,0 +1,11 @@
+using FileTime.Core.Models;
+
+namespace FileTime.Avalonia.ViewModels.ItemPreview
+{
+    public interface ISizeItemViewModel
+    {
+        string? Name { get; }
+        long? Size { get; }
+        IItem? Item { get; }
+    }
+}