feat: add new Notification.

demo/Ursa.Demo/ViewModels/NotificationDemoViewModel.cs

@@ -0,0 +1,42 @@
+using System;
+using Avalonia.Controls.Notifications;
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using Notification = Ursa.Controls.Notification;
+using WindowNotificationManager = Ursa.Controls.WindowNotificationManager;
+
+namespace Ursa.Demo.ViewModels;
+
+public partial class NotificationDemoViewModel : ObservableObject
+{
+    public WindowNotificationManager? NotificationManager { get; set; }
+
+    [ObservableProperty] private bool _showClose = true;
+
+    [RelayCommand]
+    public void ShowNormal(object obj)
+    {
+        if (obj is string s)
+        {
+            Enum.TryParse<NotificationType>(s, out var notificationType);
+            NotificationManager?.Show(
+                new Notification("Welcome", "This is message"),
+                showClose: ShowClose,
+                type: notificationType);
+        }
+    }
+
+    [RelayCommand]
+    public void ShowLight(object obj)
+    {
+        if (obj is string s)
+        {
+            Enum.TryParse<NotificationType>(s, out var notificationType);
+            NotificationManager?.Show(
+                new Notification("Welcome", "This is message"),
+                showClose: ShowClose,
+                type: notificationType,
+                classes: ["Light"]);
+        }
+    }
+}