feat: Add CanvasArea component placeholder

frontend/src/components/CanvasArea.tsx

@@ -0,0 +1,15 @@
+import React from 'react';
+import './CanvasArea.css';
+
+const CanvasArea: React.FC = () => {
+  return (
+    <div className="canvas-area" role="main" aria-label="Drawing Canvas">
+      <div className="canvas-placeholder">
+        <p>Canvas Area</p>
+        <p className="placeholder-subtext">Drawing canvas will be rendered here</p>
+      </div>
+    </div>
+  );
+};
+
+export default CanvasArea;