Fleet monitoring: sysstat 28d + perfsnap/PSI/iotop timers + on-demand toolbox container (#826)

- monitoring/node-install.sh: idempotent per-node installer (sar HISTORY=28,
  three oneshot timers, per-node conf with qemu.slice/lxc cgroup globs)
- monitoring/collectors + systemd units: iotop-snap 15min, perfsnap 60s,
  psi-textfile 15s (now sources /etc/knelperf/perfsnap.conf; multi-glob)
- monitoring/toolbox: pct LXC (vmid 950, privileged, apparmor unconfined,
  stopped at rest) + knelperf-toolbox wrapper + Dockerfile variant
- monitoring/deploy-fleet.sh: workstation-side rollout driver
- piloted on pfv-tsys1: per-VM PSI gauges verified live

Redmine: https://projects.knownelement.com/issues/826

README.md

@@ -45,6 +45,7 @@ flowchart LR
 
 | Module | What it does | Entry point |
 |---|---|---|
+| `monitoring/` | fleet instrumentation: sysstat 28d tuning, perfsnap/PSI/iotop timers, on-demand perf toolbox container (LXC on PVE nodes, Docker image for the rest) | `monitoring/deploy-fleet.sh` |
 | `loop/` | the baseline→audit→tweak→re-baseline driver, CPU bench (openssl-based), tolerance diff | `loop/perf-loop.sh baseline <host>` |
 | `scheduler/` | Ultix breakout: day/night profile engine (conf-driven redesign), PSI/perfsnap collectors, proxmox-ctl, systemd timer templates | `scheduler/README.md` |
 | `bench/` | fleet storage+network harness v1.1 (fio JSON, iperf3) | `bench/bench-run.sh` |
@@ -76,6 +77,7 @@ KNELPERF_CPUBENCH_SECS=5 ./loop/cpu-bench.sh
 | [docs/report-amt-power-telemetry.md](docs/report-amt-power-telemetry.md) | Intel AMT/vPro per-system feasibility — spoiler: no AMT version ever exposed watts; RAPL/iDRAC are the real paths |
 | [docs/report-moonlight-desktop.md](docs/report-moonlight-desktop.md) | KDE/xrdp VM → containerized desktop from k8s (webtop/KasmVNC now, Selkies on the future GPU node) |
 | [scheduler/README.md](scheduler/README.md) | Ultix breakout map, redesign deltas, 8 lessons-learned carried forward |
+| [monitoring/README.md](monitoring/README.md) | what lands on each node, toolbox cookbook, analysis recipes, prod/CR gating |
 
 Related repos: [KNEL/KNELSiterSolar](https://git.knownelement.com/KNEL/KNELSiterSolar)
 (solar economics + ONCOR arbitrage + ERCOT risk brief) ·