Add custom SVG cursors and update cursor handling

- Introduced new SVG cursor assets: cross, default, export, move, open, pen, and pointing.
- Implemented SCSS styles for cursor usage in the scene container, defining specific cursors for different modes (draw, pointer, pen, measure, hand).
- Enhanced cursor functionality by adding a utility function to handle canvas cursor changes based on user actions, mapping specific actions to corresponding cursor styles.

app/src/assets/cursors/cell.svg

@@ -0,0 +1,4 @@
+<svg width="14" height="14" viewBox="0 0 14 14" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path d="M9 5H14V9H9V14H5V9H0V5H5V0H9V5Z" fill="black"/>
+<path d="M8 6H13V8H8V13H6V8H1V6H6V1H8V6Z" fill="white"/>
+</svg>