🎨 Palette: 빈 디렉토리 상태의 아이콘 및 접근성 개선

[seonghobae]

빈 디렉토리를 렌더링할 때 단순히 "이 디렉토리는 비어 있습니다." 텍스트만 보여주지 않고, 열린 폴더 아이콘(📂)을 함께 표시하여 사용자에게 보다 직관적인 피드백을 제공합니다. 또한 장식용 아이콘을 스크린 리더가 읽지 않게 접근성을 보장하기 위해 aria-hidden="true"를 적용했으며, Flexbox CSS 속성을 사용해 아이콘과 텍스트의 정렬을 개선했습니다. 100% 테스트 커버리지가 유지되고 있음을 확인했습니다.

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PR created automatically by Jules for task 3466453610540095239 started by @seonghobae

[google-labs-jules]

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