feat: Add BindableAttribute to Uno.Foundation types for NAOT trimmer

Co-authored-by: jeromelaban <5839577+jeromelaban@users.noreply.github.com>

Author: Copilot

src/SourceGenerators/Uno.UI.SourceGenerators/Uno.UI.SourceGenerators.csproj

@@ -23,6 +23,9 @@
 	</ItemGroup>
 
 	<ItemGroup>
+		<Compile Include="..\..\Uno.Foundation\Internals\BindableAttribute.cs">
+			<Link>XamlGenerator\XamlPathParser\BindableAttribute.cs</Link>
+		</Compile>
 		<Compile Include="..\..\Uno.Foundation\Point.cs">
 			<Link>XamlGenerator\XamlPathParser\Point.cs</Link>
 		</Compile>

src/Uno.Foundation/Internals/BindableAttribute.cs

@@ -0,0 +1,19 @@
+#nullable enable
+
+using System;
+
+namespace Uno.Foundation.Internals
+{
+	/// <summary>
+	/// Marks a type as bindable for the NAOT trimmer.
+	/// This attribute is used by the BindableTypeProvidersSourceGenerator to identify types
+	/// that should have binding metadata generated, preventing them from being trimmed.
+	/// </summary>
+	[AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, Inherited = false, AllowMultiple = false)]
+	internal sealed class BindableAttribute : Attribute
+	{
+		public BindableAttribute()
+		{
+		}
+	}
+}

src/Uno.Foundation/Point.cs

@@ -11,6 +11,7 @@
 namespace Windows.Foundation;
 
 [DebuggerDisplay("{DebugDisplay,nq}")]
+[Uno.Foundation.Internals.Bindable]
 public partial struct Point
 {
 	// These are public in WinUI (with the underscore!), but we don't want to expose it for now at least.

src/Uno.Foundation/Rect.cs

@@ -9,6 +9,7 @@
 namespace Windows.Foundation;
 
 [DebuggerDisplay("[Rect {Size}@{Location}]")]
+[Uno.Foundation.Internals.Bindable]
 public partial struct Rect
 {
 	// These are public in WinUI (with the underscore!), but we don't want to expose it for now at least.

src/Uno.Foundation/Size.cs

@@ -9,6 +9,7 @@ namespace Windows.Foundation;
 
 [DebuggerDisplay("{DebugDisplay,nq}")]
 [TypeConverter(typeof(SizeConverter))]
+[Uno.Foundation.Internals.Bindable]
 public partial struct Size
 {
 	// These are public in WinUI (with the underscore!), but we don't want to expose it for now at least.