Changed the undo and redo button onclick handlers to call canvas.undo() and canvas.redo() instead of canvas.canvasState.undo() and canvas.canvasState.redo(). This aligns the button actions with the updated canvas API.
Changed the undo and redo button onclick handlers to call canvas.undo() and canvas.redo() instead of canvas.canvasState.undo() and canvas.canvasState.redo(). This aligns the button actions with the updated canvas API.