Verify handlers and fix ImageButtonHandler

Verified handlers (method-by-method comparison with decompiled):
- CheckBoxHandler, SwitchHandler, SliderHandler, ProgressBarHandler
- ImageHandler, BoxViewHandler, ScrollViewHandler, EditorHandler

Fixed:
- ImageButtonHandler: Added missing MapBackgroundColor method

Blocked:
- BorderHandler: Needs SkiaBorder.MauiView and Tapped event (View issue)

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

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

Handlers/ImageButtonHandler.cs

@@ -24,6 +24,7 @@ public partial class ImageButtonHandler : ViewHandler<IImageButton, SkiaImageBut
         [nameof(IButtonStroke.CornerRadius)] = MapCornerRadius,
         [nameof(IPadding.Padding)] = MapPadding,
         [nameof(IView.Background)] = MapBackground,
+        ["BackgroundColor"] = MapBackgroundColor,
     };
 
     public static CommandMapper<IImageButton, ImageButtonHandler> CommandMapper = new(ViewHandler.ViewCommandMapper)
@@ -154,6 +155,16 @@ public partial class ImageButtonHandler : ViewHandler<IImageButton, SkiaImageBut
         }
     }
 
+    public static void MapBackgroundColor(ImageButtonHandler handler, IImageButton imageButton)
+    {
+        if (handler.PlatformView is null) return;
+
+        if (imageButton is Microsoft.Maui.Controls.ImageButton imgBtn && imgBtn.BackgroundColor is not null)
+        {
+            handler.PlatformView.BackgroundColor = imgBtn.BackgroundColor.ToSKColor();
+        }
+    }
+
     // Image source loading helper
     private ImageSourceServiceResultManager _sourceLoader = null!;