Fix handlers to match decompiled production code

- ButtonHandler: Removed MapText/TextColor/Font (not in production), fixed namespace
- LabelHandler: Added CharacterSpacing/LayoutAlignment/FormattedText, ConnectHandler gesture logic
- EntryHandler: Added CharacterSpacing/ClearButtonVisibility/VerticalTextAlignment
- EditorHandler: Created from decompiled (was missing)
- SliderHandler: Fixed namespace, added ConnectHandler init calls
- SwitchHandler: Added OffTrackColor logic, fixed namespace
- CheckBoxHandler: Added VerticalLayoutAlignment/HorizontalLayoutAlignment
- ProgressBarHandler: Added ConnectHandler/DisconnectHandler IsVisible tracking
- PickerHandler: Created from decompiled with collection changed tracking
- ActivityIndicatorHandler: Removed IsEnabled/BackgroundColor (not in production)
- All handlers now use namespace Microsoft.Maui.Platform.Linux.Handlers
- All handlers have proper null checks on PlatformView
- Updated MERGE_TRACKING.md with accurate status

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

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

Views/SkiaBoxView.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using Microsoft.Maui.Controls;
 using SkiaSharp;
 
 namespace Microsoft.Maui.Platform;
@@ -12,11 +13,11 @@ public class SkiaBoxView : SkiaView
 {
     public static readonly BindableProperty ColorProperty =
         BindableProperty.Create(nameof(Color), typeof(SKColor), typeof(SkiaBoxView), SKColors.Transparent,
-            propertyChanged: (b, o, n) => ((SkiaBoxView)b).Invalidate());
+            BindingMode.TwoWay, propertyChanged: (b, o, n) => ((SkiaBoxView)b).Invalidate());
 
     public static readonly BindableProperty CornerRadiusProperty =
         BindableProperty.Create(nameof(CornerRadius), typeof(float), typeof(SkiaBoxView), 0f,
-            propertyChanged: (b, o, n) => ((SkiaBoxView)b).Invalidate());
+            BindingMode.TwoWay, propertyChanged: (b, o, n) => ((SkiaBoxView)b).Invalidate());
 
     public SKColor Color
     {