Site Studio: ortak arayuz dili, bolum onizleme ve editor yenileme

- site-studio bilesen/CSS katmani ve SiteStudioComposer eklendi
- Site yonetimi sayfalari (index, editor, branding, domain, submissions,
  visitor-chats) ortak studio tasarim diline gecirildi
- Bolum bazli canli onizleme (preview-section) ve SectionSampleFactory ile
  ornek veri uretimi eklendi
- Voyage sablonunda tur kataloglari, fiyat ve kategori bolumleri guncellendi

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AjpoduEBQjFpxfoqaHMkpn
