0d1b0eae4c
- Changed default VISION_BACKEND from CPU to GPU for better performance. - Made `map_brush_style` public to allow external access. - Updated `Engine` struct to use pooled buffers for stroke snapshots, reducing memory allocations during brush strokes. - Introduced `CompositeSnapshot` for efficient background compositing without blocking the UI thread. - Implemented `SendPtr` for safe raw pointer handling across threads. - Enhanced `commit_pending_history` to recycle buffers and improve performance. - Fixed cursor preview issues for procedural brushes by removing unnecessary preset synchronization. - Added tests and documentation for new features and performance improvements.