Add target node and storage overrides to single and bulk restore flows, and
track Proxmox task progress (parse_task_progress in the monitoring worker,
new ProxmoxTask progress column + migration, enriched task API responses).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
- Add notify_update_available() method to NotificationService
- Add translations for update notifications (ru/en)
- Add 'update' type to default notification types
- Add check_for_panel_updates() background task (runs every 6 hours)
- Notifications include link to settings page for easy update access
- Prevent duplicate notifications for same version
