[feat/popover-landing]: popover 컴포넌트 추가

[ramong26]

요약

1. 랜딩 페이지에 날짜 필터용 팝오버 UI를 추가
2. 공용 Calendar / Popover 컴포넌트를 구현
3. 날짜 선택 기능에 필요한 라이브러리를 추가

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주요 변경 파일

파일	설명
src/shared/ui/Calendar.tsx	react-day-picker 기반 공용 Calendar 컴포넌트 추가
src/shared/ui/Popover.tsx	Portal 기반 공용 Popover 컴포넌트 추가
src/shared/assets/icons/ChevronDown.tsx	드롭다운 표시용 ChevronDown 아이콘 추가

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변경 이유

• 사용자가 날짜 기준으로 모임 목록을 필터링할 수 있는 UI를 제공하기 위해 추가
• Calendar와 Popover를 공용 컴포넌트로 분리하여 다른 페이지에서도 재사용할 수 있도록 구성

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참고 사항

• 현재는 날짜 선택 UI만 구현되어 있으며 실제 필터링 로직은 포함되어 있지 않음
• Popover는 Context + Portal 기반으로 구현하여 부모 레이아웃 및 overflow 영향을 받지 않도록 구성

[gemini-code-assist]

Code Review

This pull request introduces a date filtering feature on the landing page by adding new custom Calendar and Popover UI components, along with dependencies like react-day-picker and date-fns. Feedback focuses on critical fixes and enhancements: correcting the lucide-react import syntax and fixing a CSS variable syntax error in Calendar.tsx to prevent compilation and layout issues; adding scroll position offsets and outside-click/Escape key event listeners in Popover.tsx to ensure correct positioning and usability; and removing unused empty <div> elements in LandingPage.tsx for cleaner code.

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[chatgpt-codex-connector]

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