feat: finish new play page

src/components/BackButton.tsx

@@ -0,0 +1,13 @@
+import { ArrowLeft } from 'lucide-react';
+
+export function BackButton() {
+  return (
+    <button
+      onClick={() => window.history.back()}
+      className='w-10 h-10 p-2 rounded-full flex items-center justify-center text-gray-600 hover:bg-gray-200/50 dark:text-gray-300 dark:hover:bg-gray-700/50 transition-colors'
+      aria-label='Back'
+    >
+      <ArrowLeft className='w-full h-full' />
+    </button>
+  );
+}