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/EntryHandler.cs

@@ -3,6 +3,7 @@
 
 using Microsoft.Maui.Handlers;
 using Microsoft.Maui.Graphics;
+using Microsoft.Maui.Controls;
 using SkiaSharp;
 
 namespace Microsoft.Maui.Platform.Linux.Handlers;
@@ -31,6 +32,7 @@ public partial class EntryHandler : ViewHandler<IEntry, SkiaEntry>
         [nameof(ITextAlignment.HorizontalTextAlignment)] = MapHorizontalTextAlignment,
         [nameof(ITextAlignment.VerticalTextAlignment)] = MapVerticalTextAlignment,
         [nameof(IView.Background)] = MapBackground,
+        ["BackgroundColor"] = MapBackgroundColor,
     };
 
     public static CommandMapper<IEntry, EntryHandler> CommandMapper = new(ViewHandler.ViewCommandMapper)
@@ -212,4 +214,17 @@ public partial class EntryHandler : ViewHandler<IEntry, SkiaEntry>
             handler.PlatformView.BackgroundColor = solidPaint.Color.ToSKColor();
         }
     }
+
+    public static void MapBackgroundColor(EntryHandler handler, IEntry entry)
+    {
+        if (handler.PlatformView is null) return;
+
+        if (entry is Entry ve && ve.BackgroundColor != null)
+        {
+            Console.WriteLine($"[EntryHandler] MapBackgroundColor: {ve.BackgroundColor}");
+            var color = ve.BackgroundColor.ToSKColor();
+            Console.WriteLine($"[EntryHandler] Setting EntryBackgroundColor to: {color}");
+            handler.PlatformView.EntryBackgroundColor = color;
+        }
+    }
 }