chore: rename composables folder

src/composables/use-placeholder.tsx

@@ -0,0 +1,16 @@
+import { useHeight } from './use-height';
+import type { Ref } from 'vue';
+import type { BEM } from '../utils/create/bem';
+
+export function usePlaceholder(contentRef: Ref<Element>, bem: BEM) {
+  const height = useHeight(contentRef);
+
+  return (renderContent: () => JSX.Element) => (
+    <div
+      class={bem('placeholder')}
+      style={{ height: height.value ? `${height.value}px` : undefined }}
+    >
+      {renderContent()}
+    </div>
+  );
+}