Refactor Image to cache and reuse vector raster surfaces

- Add per-control bitmap cache for vector sources
- Move vector rendering and cache logic to partial class
- Replace raster cache dictionary with single image/factory
- Update cache invalidation and disposal for both paths
- Mark vector cache stale on content/tint/source changes
- Remove old direct vector rendering method

Release bitmap caches when culled or hidden

- Add subtree bitmap cache release/restore logic to UIElement
- Track cache release state with a private field
- Update rendering and visibility handling for cache lifecycle
- Document cache release behavior in CacheMode remarks

Reorder Transform section before Shapes in GalleryView

- Improves logical grouping of sections in the UI navigation

Update Aprillz.MewUI to 0.15.1 and fix class closure

- Ensures correct package version and closes ExpressionEvaluator class

Make window extension methods generic for Window subclasses

- Enables fluent usage with custom window types
- Improves API flexibility without changing functionality

Bump version to 0.14.0 in MewUI.Common.props

- Prepares for new release with updated version number

Bump MewUI version to 0.13.3

- Prepares for new release with updated version identifier

Bump MewUI version to 0.13.2

- Prepares for new release with updated versioning

Bump MewUI version to 0.13.1

- Prepares for new release with updated version identifier

Update MewUI and MewVG versions in props file

- Enables use of latest features and improvements in dependencies