Major production merge: GTK support, context menus, and dispatcher fixes

Core Infrastructure:
- Add Dispatching folder with LinuxDispatcher, LinuxDispatcherProvider, LinuxDispatcherTimer
- Add Native folder with P/Invoke wrappers (GTK, GLib, GDK, Cairo, WebKit)
- Add GTK host window system with GtkHostWindow and GtkSkiaSurfaceWidget
- Update LinuxApplication with GTK mode, theme handling, and icon support
- Fix duplicate LinuxDispatcher in LinuxMauiContext

Handlers:
- Add GtkWebViewManager and GtkWebViewPlatformView for GTK WebView
- Add FlexLayoutHandler and GestureManager
- Update multiple handlers with ToViewHandler fix and missing mappers
- Add MauiHandlerExtensions with ToViewHandler extension method

Views:
- Add SkiaContextMenu with hover, keyboard, and dark theme support
- Add LinuxDialogService with context menu management
- Add SkiaFlexLayout for flex container support
- Update SkiaShell with RefreshTheme, MauiShell, ContentRenderer
- Update SkiaWebView with SetMainWindow, ProcessGtkEvents
- Update SkiaImage with LoadFromBitmap method

Services:
- Add AppInfoService, ConnectivityService, DeviceDisplayService, DeviceInfoService
- Add GtkHostService, GtkContextMenuService, MauiIconGenerator

Window:
- Add CursorType enum and GtkHostWindow
- Update X11Window with SetIcon, SetCursor methods

Build: SUCCESS (0 errors)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Handlers/CheckBoxHandler.cs

@@ -18,6 +18,7 @@ public partial class CheckBoxHandler : ViewHandler<ICheckBox, SkiaCheckBox>
         [nameof(ICheckBox.IsChecked)] = MapIsChecked,
         [nameof(ICheckBox.Foreground)] = MapForeground,
         [nameof(IView.Background)] = MapBackground,
+        [nameof(IView.IsEnabled)] = MapIsEnabled,
         [nameof(IView.VerticalLayoutAlignment)] = MapVerticalLayoutAlignment,
         [nameof(IView.HorizontalLayoutAlignment)] = MapHorizontalLayoutAlignment,
     };
@@ -86,6 +87,12 @@ public partial class CheckBoxHandler : ViewHandler<ICheckBox, SkiaCheckBox>
         }
     }
 
+    public static void MapIsEnabled(CheckBoxHandler handler, ICheckBox checkBox)
+    {
+        if (handler.PlatformView is null) return;
+        handler.PlatformView.IsEnabled = checkBox.IsEnabled;
+    }
+
     public static void MapVerticalLayoutAlignment(CheckBoxHandler handler, ICheckBox checkBox)
     {
         if (handler.PlatformView is null) return;