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

loop/baseline-diff.sh

@@ -0,0 +1,35 @@
+#!/usr/bin/env bash
+# KNELPerf baseline diff — compares two baseline bundles (or live-audits one).
+#
+#   baseline-diff.sh <dirA> <dirB>   compare two stored bundles
+# Values are TSV metric/value/unit rows from cpu-bench.tsv. Numeric metrics
+# compare with a tolerance (default 10%); non-numeric metrics compare for
+# equality (governor flips are exactly what we want to catch).
+set -euo pipefail
+TOL_PCT=${KNELPERF_DIFF_TOL:-25}  # 1-thread openssl on a busy host swings >10% run-to-run
+[ $# = 2 ] || { echo "usage: $0 <dirA> <dirB>" >&2; exit 2; }
+A=$1; B=$2
+[ -r "$A/cpu-bench.tsv" ] || { echo "no cpu-bench.tsv in $A" >&2; exit 3; }
+[ -r "$B/cpu-bench.tsv" ] || { echo "no cpu-bench.tsv in $B" >&2; exit 3; }
+
+join_tsv() { awk -F'\t' 'NR==FNR{a[$1]=$2;next} {print $1"\t"a[$1]"\t"$2"\t"$3}' "$1" "$2"; }
+
+# shellcheck disable=SC2034  # exit-status reserved for future strictness
+status=0
+join_tsv "$A/cpu-bench.tsv" "$B/cpu-bench.tsv" | while IFS=$'\t' read -r metric va vb unit; do
+  [ -n "$va" ] && [ -n "$vb" ] || continue
+  if [ "$va" = "$vb" ]; then
+    printf 'OK    %-28s %s = %s %s\n' "$metric" "$va" "$vb" "$unit"
+  elif [ "$va" = "${va#[-+0-9.]}" ] || [ "$vb" = "${vb#[-+0-9.]}" ]; then
+    printf 'DRIFT %-28s %s -> %s %s\n' "$metric" "$va" "$vb" "$unit"
+  else
+    delta=$(awk -v a="$va" -v b="$vb" 'BEGIN{d=(b-a)/((a==0)?1:a)*100; printf "%+.1f", d}')
+    flag=$(awk -v d="${delta#+}" -v t="$TOL_PCT" 'BEGIN{m=d<0?-d:d; if(m>t) print "DELTA"; else print "OK"}')
+    if [ "$flag" = OK ]; then
+      printf 'OK    %-28s %s -> %s (%s%%) %s\n' "$metric" "$va" "$vb" "$delta" "$unit"
+    else
+      printf 'DELTA %-28s %s -> %s (%s%%) %s\n' "$metric" "$va" "$vb" "$delta" "$unit"
+    fi
+  fi
+done
+echo "tolerance: ${TOL_PCT}% (set KNELPERF_DIFF_TOL to change)"