- DB: pages.share_mode (private/invited/anyone) + published (bool)
- API: POST /board/api/share/{id} saves share settings to DB
- view_page: passes page_share_mode + page_published to template
- page_editor: inits share state from server, auto-saves on change
- Clipboard: fallback to textarea for HTTP (navigator.clipboard blocked)
- Toast: showToast() with proper timeout clearing