添加消息通知功能，使用Handy Control的Grow来实现的

Models/Notification.cs

@@ -0,0 +1,10 @@
+using PMSWPF.Enums;
+
+namespace PMSWPF.Models;
+
+public class Notification
+{
+    public string Message { get; set; }
+    public NotificationType Type { get; set; }
+    public bool IsGlobal { get; set; }
+}