- Change ping interval from 60s to 30s (configurable via PING_INTERVAL)
- Change SSH info sync from every ping to every 10 minutes (via ssh_synced_at)
- Add SSH command timeout (8s) to prevent hanging on unresponsive hosts
- Add concurrency limit (5) for SSH sync operations
- Change frontend UI refresh interval from 10s to 30s
- Fix: remove hardcoded 30s step, use configured interval directly
- Fix: ensure ping loop continues even if individual machine fails