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>

Services/VirtualizationManager.cs

@@ -202,106 +202,3 @@ public class VirtualizationManager<T> where T : SkiaView
         }
     }
 }
-
-/// <summary>
-/// Extension methods for virtualization.
-/// </summary>
-public static class VirtualizationExtensions
-{
-    /// <summary>
-    /// Calculates visible item range for a vertical list.
-    /// </summary>
-    /// <param name="scrollOffset">Current scroll offset.</param>
-    /// <param name="viewportHeight">Height of visible area.</param>
-    /// <param name="itemHeight">Height of each item (fixed).</param>
-    /// <param name="itemSpacing">Spacing between items.</param>
-    /// <param name="totalItems">Total number of items.</param>
-    /// <returns>Tuple of (firstVisible, lastVisible) indices.</returns>
-    public static (int first, int last) CalculateVisibleRange(
-        float scrollOffset,
-        float viewportHeight,
-        float itemHeight,
-        float itemSpacing,
-        int totalItems)
-    {
-        if (totalItems == 0)
-            return (-1, -1);
-
-        var rowHeight = itemHeight + itemSpacing;
-        var first = Math.Max(0, (int)(scrollOffset / rowHeight));
-        var last = Math.Min(totalItems - 1, (int)((scrollOffset + viewportHeight) / rowHeight) + 1);
-
-        return (first, last);
-    }
-
-    /// <summary>
-    /// Calculates visible item range for variable height items.
-    /// </summary>
-    /// <param name="scrollOffset">Current scroll offset.</param>
-    /// <param name="viewportHeight">Height of visible area.</param>
-    /// <param name="getItemHeight">Function to get height of item at index.</param>
-    /// <param name="itemSpacing">Spacing between items.</param>
-    /// <param name="totalItems">Total number of items.</param>
-    /// <returns>Tuple of (firstVisible, lastVisible) indices.</returns>
-    public static (int first, int last) CalculateVisibleRangeVariable(
-        float scrollOffset,
-        float viewportHeight,
-        Func<int, float> getItemHeight,
-        float itemSpacing,
-        int totalItems)
-    {
-        if (totalItems == 0)
-            return (-1, -1);
-
-        int first = 0;
-        float cumulativeHeight = 0;
-
-        // Find first visible
-        for (int i = 0; i < totalItems; i++)
-        {
-            var itemHeight = getItemHeight(i);
-            if (cumulativeHeight + itemHeight > scrollOffset)
-            {
-                first = i;
-                break;
-            }
-            cumulativeHeight += itemHeight + itemSpacing;
-        }
-
-        // Find last visible
-        int last = first;
-        var endOffset = scrollOffset + viewportHeight;
-        for (int i = first; i < totalItems; i++)
-        {
-            var itemHeight = getItemHeight(i);
-            if (cumulativeHeight > endOffset)
-            {
-                break;
-            }
-            last = i;
-            cumulativeHeight += itemHeight + itemSpacing;
-        }
-
-        return (first, last);
-    }
-
-    /// <summary>
-    /// Calculates visible item range for a grid layout.
-    /// </summary>
-    public static (int firstRow, int lastRow) CalculateVisibleGridRange(
-        float scrollOffset,
-        float viewportHeight,
-        float rowHeight,
-        float rowSpacing,
-        int totalRows)
-    {
-        if (totalRows == 0)
-            return (-1, -1);
-
-        var effectiveRowHeight = rowHeight + rowSpacing;
-        var first = Math.Max(0, (int)(scrollOffset / effectiveRowHeight));
-        var last = Math.Min(totalRows - 1, (int)((scrollOffset + viewportHeight) / effectiveRowHeight) + 1);
-
-        return (first, last);
-    }
-}