feat: enhance accessibility by adding ARIA attributes and focus styles; improve canvas and button elements

view/CanvasViewport.tsx

@@ -42,7 +42,14 @@ export function CanvasViewport({
   const hasBrushPreview = Boolean(cursorState.hasBrushPreview && !brushHint && canPreviewBrush(cursorState.document, cursorState.editor));
   const cursorClass = canvasCursorClass(cursorState.editor.tools.interactionMode, cursorState.isPanning, hasBrushPreview, !brushHint);
 
-  return <canvas ref={canvasRef} className={`h-full w-full ${cursorClass}`} />;
+  return (
+    <canvas
+      ref={canvasRef}
+      className={`h-full w-full touch-none ${cursorClass}`}
+      role="img"
+      aria-label="Image editing canvas. Use the tools and layers controls to edit the document."
+    />
+  );
 }
 
 type CanvasCursorState = {