feat:Implements subtle animations for the NavMenu in a non-intrusive way.

demo/Ursa.Demo/Pages/NavMenuDemo.axaml.cs

@@ -1,11 +1,22 @@
 using Avalonia.Controls;
+using Avalonia.Interactivity;
+using Ursa.Controls;
 
 namespace Ursa.Demo.Pages;
 
 public partial class NavMenuDemo : UserControl
 {
+    private readonly WHAnimationHelper _animationHelper;
+
     public NavMenuDemo()
     {
         InitializeComponent();
+        _animationHelper = new WHAnimationHelper(menu, NavMenu.IsHorizontalCollapsedProperty);
+    }
+
+    protected override void OnLoaded(RoutedEventArgs e)
+    {
+        base.OnLoaded(e);
+        _animationHelper.Start();
     }
 }