Add an NS1-host NATS study: run, charts, methodology, and tuning notes.

Second ladder executed entirely on NS1.GEORGELAMBERT.ORG (70.88.205.138)
against LXC 511–513; HTML and PDF built on that host.

packages/verae-nats-cluster/scripts/study-on-ns1.sh

@@ -0,0 +1,91 @@
+#!/usr/bin/env bash
+# Full message-speed study. Must run ON NS1.GEORGELAMBERT.ORG (70.88.205.138).
+# Orchestration, nats bench (via pct into LXC 510), charts, HTML, and PDF all
+# happen on this host. The laptop is not in the measurement path.
+set -euo pipefail
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+export PATH="/usr/sbin:/usr/bin:/bin:/usr/local/bin:$PATH"
+
+HOST="$(hostname -f 2>/dev/null || hostname)"
+case "$HOST" in
+  NS1.GEORGELAMBERT.ORG|NS1|ns1.georgelambert.org|ns1) ;;
+  *)
+    echo "refusing: study-on-ns1.sh must run on NS1.GEORGELAMBERT.ORG (70.88.205.138), got '$HOST'" >&2
+    exit 1
+    ;;
+esac
+
+# shellcheck disable=SC1091
+. "$ROOT/client.env"
+CLIENT_VMID="${CLIENT_VMID:-510}"
+STAMP="$(date -u +%Y%m%dT%H%M%SZ)"
+OUT="${BENCH_OUT:-$ROOT/results/$STAMP}"
+mkdir -p "$OUT"
+
+dump_env() {
+  local tag="$1"
+  local f="$OUT/host-$tag.txt"
+  {
+    echo "execution_host=NS1.GEORGELAMBERT.ORG"
+    echo "execution_ip=70.88.205.138"
+    echo "hostname=$(hostname)"
+    echo "utc=$(date -u +%Y-%m-%dT%H:%M:%SZ)"
+    echo "whoami=$(whoami)"
+    echo "pwd=$(pwd)"
+    echo "uname=$(uname -a)"
+    echo "nproc=$(nproc)"
+    echo "loadavg=$(cat /proc/loadavg)"
+    echo "client_vmid=$CLIENT_VMID"
+    echo "nats_url=$NATS_URL"
+    echo "--- free ---"
+    free -h
+    echo "--- pct list ---"
+    sudo pct list
+    for v in 510 511 512 513; do
+      echo "--- pct config $v ---"
+      sudo pct config "$v" | grep -E '^(hostname|cores|memory|swap|rootfs|mp|net)' || true
+    done
+  } >"$f"
+  python3 - "$OUT" "$tag" <<'PY'
+import json, sys, urllib.request
+from pathlib import Path
+out, tag = Path(sys.argv[1]), sys.argv[2]
+nodes = []
+for vmid, name in (("511", "nats-a"), ("512", "nats-b"), ("513", "nats-c")):
+    raw = ""
+    try:
+        import subprocess
+        raw = subprocess.check_output(
+            ["sudo", "pct", "exec", vmid, "--", "curl", "-fsS", "--max-time", "3", "http://127.0.0.1:8222/varz"],
+            text=True,
+        )
+        d = json.loads(raw)
+        nodes.append({
+            "vmid": vmid,
+            "name": name,
+            "server_name": d.get("server_name"),
+            "host": d.get("host"),
+            "port": d.get("port"),
+            "connections": d.get("connections"),
+            "in_msgs": d.get("in_msgs"),
+            "out_msgs": d.get("out_msgs"),
+            "in_bytes": d.get("in_bytes"),
+            "out_bytes": d.get("out_bytes"),
+            "cpu": d.get("cpu"),
+            "cores": d.get("cores"),
+            "mem": d.get("mem"),
+            "jetstream": bool(d.get("jetstream")),
+        })
+    except Exception as e:
+        nodes.append({"vmid": vmid, "name": name, "error": str(e)})
+(out / f"varz-{tag}.json").write_text(json.dumps(nodes, indent=2) + "\n", encoding="utf-8")
+PY
+}
+
+echo "NS1 study $STAMP  out=$OUT"
+dump_env before
+BENCH_OUT="$OUT" CLIENT_VMID="$CLIENT_VMID" bash "$ROOT/scripts/bench.sh"
+dump_env after
+python3 "$ROOT/scripts/build-ns1-study-report.py" "$OUT"
+echo "NS1 study complete $OUT"
+ls -la "$OUT"/nats-cluster-bench-ns1.* "$OUT"/charts 2>/dev/null || ls -la "$OUT"