- Seed/update admin user from ADMIN_USERNAME/ADMIN_PASSWORD settings on
startup (admin_users table was empty, login was impossible)
- POST /api/admin/sync now returns immediately and runs the equipment
sync via BackgroundTasks (full sync took minutes and hit nginx 504)
- run_sync accepts optional sync_log_id to reuse a pre-created log entry
- Adapt admin router test to background sync behavior