Verify Views files against decompiled, extract embedded types

Fixed files:
- SkiaImageButton.cs: Added SVG support with multi-path search
- SkiaNavigationPage.cs: Added LinuxApplication.IsGtkMode check
- SkiaRefreshView.cs: Added ICommand support (Command, CommandParameter)
- SkiaTemplatedView.cs: Added missing using statements

Extracted embedded types to separate files (matching decompiled pattern):
- From SkiaMenuBar.cs: MenuBarItem, MenuItem, SkiaMenuFlyout, MenuItemClickedEventArgs
- From SkiaNavigationPage.cs: NavigationEventArgs
- From SkiaTabbedPage.cs: TabItem
- From SkiaVisualStateManager.cs: SkiaVisualStateGroupList, SkiaVisualStateGroup, SkiaVisualState, SkiaVisualStateSetter
- From SkiaSwipeView.cs: SwipeItem, SwipeStartedEventArgs, SwipeEndedEventArgs
- From SkiaFlyoutPage.cs: FlyoutLayoutBehavior (already separate)
- From SkiaIndicatorView.cs: IndicatorShape (already separate)
- From SkiaBorder.cs: SkiaFrame
- From SkiaCarouselView.cs: PositionChangedEventArgs
- From SkiaCollectionView.cs: SkiaSelectionMode, ItemsLayoutOrientation
- From SkiaContentPresenter.cs: LayoutAlignment

Verified matching decompiled:
- SkiaContextMenu.cs, SkiaFlexLayout.cs, SkiaGraphicsView.cs

Build: 0 errors

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

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

Views/SkiaCollectionView.cs

@@ -9,25 +9,6 @@ using SkiaSharp;
 
 namespace Microsoft.Maui.Platform;
 
-/// <summary>
-/// Selection mode for collection views.
-/// </summary>
-public enum SkiaSelectionMode
-{
-    None,
-    Single,
-    Multiple
-}
-
-/// <summary>
-/// Layout orientation for items.
-/// </summary>
-public enum ItemsLayoutOrientation
-{
-    Vertical,
-    Horizontal
-}
-
 /// <summary>
 /// Skia-rendered CollectionView with selection, headers, and flexible layouts.
 /// </summary>