Add agentapi HostMetrics() + a thin /api/host-metrics proxy to the agent's
new GET /host/metrics, and a 'Szerver allapota (gazdagep)' card on the
monitoring page rendering host CPU%/load/mem/CPU-temp(n/a)/uptime + per-
storage capacity bars (thin-pool fill, disk temp/wear). Polls every 8s.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
