feat: auth system, scrip scheduler, UI widgets, and new API routes
- Add session-based authentication (login page, middleware, auth context)
- Add cron-like scrip scheduler for time-based conditions
- Add layout builder, scrip wizard, searchable select components
- Add trend chart widget for dashboards
- Add notifications, attachments, queue-permissions API routes
- Add seed-users script
- Update schema with 10 new migrations (0008-0017)
- Apply redesign: Linear-inspired dark theme, conversation-centric UI
- Gitignore runtime data directory
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>