fix: Use IReadOnlyList for menu items to avoid unnecessary copies

Co-authored-by: MartinZikmund <1075116+MartinZikmund@users.noreply.github.com>

Author: Copilot

src/Uno.UI.Runtime.Skia.MacOS/UI/NativeMenu/MacOSNativeMenuBarExtension.cs

@@ -27,7 +27,7 @@ public static void Register()
 
 	public bool IsSupported => true;
 
-	public void Apply(IList<NativeMenuItem> items)
+	public void Apply(IReadOnlyList<NativeMenuItem> items)
 	{
 		// Clear existing menus first
 		NativeMenuInterop.uno_menu_bar_clear();

src/Uno.UWP/UI/NativeMenu/INativeMenuBarExtension.skia.cs

@@ -19,6 +19,6 @@ internal interface INativeMenuBarExtension
 	/// Applies the menu items to the native menu bar.
 	/// </summary>
 	/// <param name="items">The collection of top-level menu items to apply.</param>
-	void Apply(IList<NativeMenuItem> items);
+	void Apply(IReadOnlyList<NativeMenuItem> items);
 }
 #endif

src/Uno.UWP/UI/NativeMenu/NativeMenuBar.iOS.cs

@@ -19,7 +19,7 @@ partial void ApplyNativeMenuPartial()
 	{
 		// On iOS, menu bar integration requires buildMenu(with:) to be called from the UIApplicationDelegate.
 		// This implementation stores the menu structure to be used when the system requests menu building.
-		NativeMenuBridgeiOS.SetMenuItems(_items.ToList());
+		NativeMenuBridgeiOS.SetMenuItems(_items);
 	}
 }
 
@@ -28,9 +28,9 @@ partial void ApplyNativeMenuPartial()
 /// </summary>
 internal static class NativeMenuBridgeiOS
 {
-	private static List<NativeMenuItem>? _menuItems;
+	private static IReadOnlyList<NativeMenuItem>? _menuItems;
 
-	internal static void SetMenuItems(List<NativeMenuItem> items)
+	internal static void SetMenuItems(IReadOnlyList<NativeMenuItem> items)
 	{
 		_menuItems = items;
 	}
@@ -42,7 +42,7 @@ internal static void SetMenuItems(List<NativeMenuItem> items)
 	/// <param name="builder">The UIMenuBuilder provided by iOS.</param>
 	public static void BuildMenu(IUIMenuBuilder builder)
 	{
-		if (_menuItems == null || !_menuItems.Any())
+		if (_menuItems == null || _menuItems.Count == 0)
 		{
 			return;
 		}

src/Uno.UWP/UI/NativeMenu/NativeMenuBar.skia.cs

@@ -1,7 +1,6 @@
 #if __SKIA__
 #nullable enable
 
-using System.Linq;
 using Uno.Foundation.Extensibility;
 
 namespace Uno.UI.NativeMenu;
@@ -18,7 +17,7 @@ static partial void IsNativeMenuSupportedPartial(ref bool isSupported)
 
 	partial void ApplyNativeMenuPartial()
 	{
-		GetExtension()?.Apply(_items.ToList());
+		GetExtension()?.Apply(_items);
 	}
 
 	private static INativeMenuBarExtension? GetExtension()