feat: add notification card and notification manager

src/Semi.Avalonia.Demo/MainWindow.axaml.cs

@@ -1,13 +1,29 @@
+using System.Diagnostics;
 using Avalonia.Controls;
+using Avalonia.Controls.Notifications;
+using Avalonia.Controls.Primitives;
 using Avalonia.Interactivity;
+using Avalonia.Layout;
+using Avalonia.VisualTree;
 
 namespace Semi.Avalonia.Demo
 {
     public partial class MainWindow : Window
     {
+        private readonly WindowNotificationManager _manager;
         public MainWindow()
         {
             InitializeComponent();
+            _manager = new WindowNotificationManager(this)
+            {
+                Position = NotificationPosition.TopLeft,
+                MaxItems = 3
+            };
+        }
+
+        internal void Notify(NotificationType t)
+        {
+            _manager.Show(new Notification(t.ToString(), "This is a notification message", t));
         }
     }
 }