- Migrate GhostObject to Ghost.Editor.Core to support weak-reference instance tracking, modification hooks, and state serialization
- Implement IDirtyTrackerService to track dirty objects and assets based on UndoService version tracking
- Update SceneAssetHandler to save scene assets via SceneSerializationService and register scene instances on load
- Refactor entity hierarchy sorting in SceneSerializationService to use high-performance UnsafeList and UnsafeHashMap structures
- Introduce ShortcutAttribute and update MenuUtility to support keyboard accelerators on menu items
- Map Ctrl+S shortcut to save dirty assets using the new File/Save command
