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/SkiaActivityIndicator.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;
@@ -21,6 +22,7 @@ public class SkiaActivityIndicator : SkiaView
             typeof(bool),
             typeof(SkiaActivityIndicator),
             false,
+            BindingMode.TwoWay,
             propertyChanged: (b, o, n) => ((SkiaActivityIndicator)b).OnIsRunningChanged());
 
     /// <summary>
@@ -32,6 +34,7 @@ public class SkiaActivityIndicator : SkiaView
             typeof(SKColor),
             typeof(SkiaActivityIndicator),
             new SKColor(0x21, 0x96, 0xF3),
+            BindingMode.TwoWay,
             propertyChanged: (b, o, n) => ((SkiaActivityIndicator)b).Invalidate());
 
     /// <summary>
@@ -43,6 +46,7 @@ public class SkiaActivityIndicator : SkiaView
             typeof(SKColor),
             typeof(SkiaActivityIndicator),
             new SKColor(0xBD, 0xBD, 0xBD),
+            BindingMode.TwoWay,
             propertyChanged: (b, o, n) => ((SkiaActivityIndicator)b).Invalidate());
 
     /// <summary>
@@ -54,6 +58,7 @@ public class SkiaActivityIndicator : SkiaView
             typeof(float),
             typeof(SkiaActivityIndicator),
             32f,
+            BindingMode.TwoWay,
             propertyChanged: (b, o, n) => ((SkiaActivityIndicator)b).InvalidateMeasure());
 
     /// <summary>
@@ -65,6 +70,7 @@ public class SkiaActivityIndicator : SkiaView
             typeof(float),
             typeof(SkiaActivityIndicator),
             3f,
+            BindingMode.TwoWay,
             propertyChanged: (b, o, n) => ((SkiaActivityIndicator)b).InvalidateMeasure());
 
     /// <summary>
@@ -75,7 +81,8 @@ public class SkiaActivityIndicator : SkiaView
             nameof(RotationSpeed),
             typeof(float),
             typeof(SkiaActivityIndicator),
-            360f);
+            360f,
+            BindingMode.TwoWay);
 
     /// <summary>
     /// Bindable property for ArcCount.
@@ -86,6 +93,7 @@ public class SkiaActivityIndicator : SkiaView
             typeof(int),
             typeof(SkiaActivityIndicator),
             12,
+            BindingMode.TwoWay,
             propertyChanged: (b, o, n) => ((SkiaActivityIndicator)b).Invalidate());
 
     #endregion