⚡ Bolt: content-visibility를 활용한 렌더링 성능 최적화

[seonghobae]

💡 What: styles.css의 .section 클래스에 content-visibility: auto를 적용하고, 각 섹션 요소에 스크롤바 점핑 및 레이아웃 시프트 방지를 위한 contain-intrinsic-size를 지정했습니다.
🎯 Why: 긴 페이지에서 화면 밖(off-screen)에 있는 섹션들의 렌더링을 지연시킴으로써, 브라우저가 초기 페인트(Time to Interactive)에 집중할 수 있도록 하여 성능(렌더링 시간 및 메모리 사용량)을 향상시키기 위함입니다.
📊 Impact: 브라우저가 렌더링을 최적화할 수 있어 초기 로드 속도가 향상되며, TTI (Time to Interactive) 지표가 개선됩니다.
🔬 Measurement: 브라우저 개발자 도구의 Performance 탭을 통해 초기 렌더링 및 레이아웃 시간 감소 효과를 확인할 수 있으며, 추가된 Playwright 스크립트를 통해 CSS 속성이 올바르게 반영되었음을 검증했습니다.

---

PR created automatically by Jules for task 9765345728441618140 started by @seonghobae

[google-labs-jules]

👋 Jules, reporting for duty! I'm here to lend a hand with this pull request.

When you start a review, I'll add a 👀 emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down.

I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job!

For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with @jules. You can find this option in the Pull Request section of your global Jules UI settings. You can always switch back!

New to Jules? Learn more at jules.google/docs.

---

For security, I will only act on instructions from the user who triggered this task.

[seonghobae]

Closed as superseded: after merging current main, this PR has no remaining file diff. The content-visibility fallback policy and regression tests are already present on main. Local verification on the resolved branch: pytest tests -q (2 passed), git diff --check, CodeGraph status OK.

[google-labs-jules]

Closed as superseded: after merging current main, this PR has no remaining file diff. The content-visibility fallback policy and regression tests are already present on main. Local verification on the resolved branch: pytest tests -q (2 passed), git diff --check, CodeGraph status OK.

알겠습니다. 이 작업은 이미 메인에 반영되어 더 이상 필요하지 않으므로 변경 사항을 정리하고 작업을 종료하겠습니다.