- Replace bell dropdown with full-screen NotificationsModal (mirrors SearchModal pattern)
- Notifications visible to all logged-in users (not just admin)
- Admin users excluded from new-chapter fan-out (dedup vs Scrape Complete notification)
- Users with notify_new_chapters=false opted out of new-chapter in-app notifications
- Toggle in profile page to enable/disable in-app new-chapter notifications
- PATCH /api/profile endpoint to save notification preferences
- User-facing /notifications page (admin redirects to /admin/notifications)