🎨 Palette: 빈 디렉토리 상태의 접근성 및 시각적 일관성 개선

[seonghobae]

💡 What: 빈 디렉토리 메시지 영역에 flexbox 레이아웃을 적용하고, 폴더 아이콘(📂) 및 시맨틱 역할(role="status")을 추가했습니다.
🎯 Why: 스크린 리더 환경에서 정적인 디렉토리 빈 상태 목록이 명확하게 안내되지 않는 문제를 해결하고, 시각적으로 목록 내 다른 링크 항목들과 일관성을 유지하기 위함입니다.
📸 Before/After: N/A (시각적 변경 및 접근성 향상)
♿ Accessibility: role="status"를 추가하여 스크린 리더 사용자가 의도된 빈 목록임을 인식할 수 있도록 하고, 장식용 아이콘에는 aria-hidden="true"를 적용했습니다.

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PR created automatically by Jules for task 15729574947694873148 started by @seonghobae

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