Allow users to customize when they receive notification reminders:
- Add task_due_soon_hour, task_overdue_hour, warranty_expiring_hour fields
- Store times in UTC, clients convert to/from local timezone
- Worker runs hourly, queries only users scheduled for that hour
- Early exit optimization when no users need notifications
- Admin UI displays custom notification times
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>