Add drag-to-reposition for selected elements in the SVG preview.
- Drag selected element(s) in preview to reposition
- Update transform, x/y, or cx/cy attributes in the editor accordingly
- Support single and multi-select (Ctrl+click)
- Show guides/snapping during drag (optional)
- Sync editor and preview on drop
Add drag-to-reposition for selected elements in the SVG preview.