KNELPerf v2 wave 1: Ultix scheduler breakout + loop skeleton + reports (#826)

- scheduler/: day/night engine (conf-driven redesign), psi/perfsnap collectors,
  proxmox-ctl, systemd timer templates — ported from ~/projects/ultix per the
  breakout map in scheduler/README.md
- loop/: perf-loop driver (baseline/audit/tweak/rebaseline), cpu-bench (new CPU
  leg), baseline-diff (tolerance compare) — smoke-tested locally
- docs/ARCHITECTURE.md: full program design (loop, resource groups, VM/spindle
  balancing, k8s-vs-Slurm, beszel+RAPL/iDRAC telemetry spine, workload classes,
  solar/HA + two-site power economics)
- docs/report-amt-power-telemetry.md + docs/report-moonlight-desktop.md

Redmine: https://projects.knownelement.com/issues/826#note-2

scheduler/collectors/knelperf-perfsnap.sh

@@ -0,0 +1,55 @@
+#!/usr/bin/env bash
+# KNELPerf perfsnap — periodic /proc+cgroupfs snapshot collector.
+# Ported from ultix staged/reachableceo-perfsnap.sh (#826); generalizations:
+#   - watched cgroups and interfaces are env/conf-driven lists (no baked-in
+#     user ids or NIC names)
+#   - log dir env-driven; same pipe-delimited format for awk analysis
+#
+# Env (or /etc/knelperf/perfsnap.conf):
+#   KNELPERF_PERF_LOGDIR   default /var/log/knelperf-perf
+#   KNELPERF_SNAP_CGROUPS  space-separated "label:/sys/fs/cgroup/path" list
+#   KNELPERF_SNAP_IFACES   space-separated interface names
+# Fields (snap.log): ts|l1|l5|l15|run|blocked|memavail_kb|psi_cpu|psi_mem|
+#   psi_io|<cgroup usage_usec per label>|<iface rx tx per label>
+# psi_* = avg60 "some" percentages. *_usec = cgroup cpu.stat usage_usec
+# (cumulative; analyze deltas).
+set -u
+CONF=/etc/knelperf/perfsnap.conf
+[ -r "$CONF" ] && . "$CONF"
+LOGDIR=${KNELPERF_PERF_LOGDIR:-/var/log/knelperf-perf}
+SNAP_CGROUPS=${KNELPERF_SNAP_CGROUPS:-}
+SNAP_IFACES=${KNELPERF_SNAP_IFACES:-}
+mkdir -p "$LOGDIR"
+ts=$(date +%s)
+
+read -r l1 l5 l15 _ < /proc/loadavg
+run=$(awk '/procs_running/{print $2}' /proc/stat)
+blocked=$(awk '/procs_blocked/{print $2}' /proc/stat)
+memavail=$(awk '/MemAvailable/{print $2}' /proc/meminfo)
+
+psi() { awk '$1=="some"{for(i=2;i<=NF;i++) if($i ~ /^avg60=/){sub("avg60=","",$i); print $i; exit}}' "/proc/pressure/$1" 2>/dev/null || echo 0; }
+
+line="$ts|$l1|$l5|$l15|$run|$blocked|$memavail|$(psi cpu)|$(psi memory)|$(psi io)"
+
+cgusec() { awk '/^usage_usec/{print $2}' "$1/cpu.stat" 2>/dev/null || echo 0; }
+for spec in $SNAP_CGROUPS; do
+  line="$line|$(cgusec "${spec#*:}")"
+done
+
+nd() { awk -v i="$1" '$1==i":":{print $2" "$10}' /proc/net/dev 2>/dev/null || echo "0 0"; }
+for ifc in $SNAP_IFACES; do
+  read -r rx tx <<< "$(nd "$ifc")"
+  line="$line|$rx|$tx"
+done
+
+echo "$line" >> "$LOGDIR/snap.log"
+
+ps -eo pcpu,pid,comm --sort=-pcpu --no-headers | head -5 \
+  | awk -v t="$ts" '{print t"|"$1"|"$2"|"$3}' >> "$LOGDIR/procs.log"
+
+# retention: 14 days; rotate anything over 50MB
+find "$LOGDIR" -name '*.log' -mtime +14 -delete 2>/dev/null
+for f in "$LOGDIR"/*.log; do
+  [ "$(wc -c <"$f" 2>/dev/null || echo 0)" -gt 52428800 ] && mv "$f" "$f.1"
+done
+exit 0