Update with recovered code from VM binaries (Jan 1)

Recovered from decompiled OpenMaui.Controls.Linux.dll:
- SkiaShell.cs: FlyoutHeader, FlyoutFooter, scroll support (918 -> 1325 lines)
- X11Window.cs: Cursor support (XCreateFontCursor, XDefineCursor)
- All handlers with dark mode support
- All services with latest implementations
- LinuxApplication with theme change handling

Services/NotificationClosedEventArgs.cs

@@ -0,0 +1,19 @@
+using System;
+
+namespace Microsoft.Maui.Platform.Linux.Services;
+
+public class NotificationClosedEventArgs : EventArgs
+{
+	public uint NotificationId { get; }
+
+	public NotificationCloseReason Reason { get; }
+
+	public string? Tag { get; }
+
+	public NotificationClosedEventArgs(uint notificationId, NotificationCloseReason reason, string? tag)
+	{
+		NotificationId = notificationId;
+		Reason = reason;
+		Tag = tag;
+	}
+}