ultix perf/ops workbench: complete 2026-08-31 optimization pass for VM 5111

Everything for the ultix-streaming (VM 5111, pfv-tsys5) performance pass:
full report + host audit results, staged/gated configs, guest prep + host
one-shot + post-reboot-fix + netcheck lifecycle scripts, grow-root manual
runbook, rolling tracking HUD, questions v1, and the gateway boot-race
hardening units. Applied and verified live 2026-08-31; open work is
tracked in Redmine project 55 as #601-#607. [#602]

💘 Generated with Crush

Assisted-by: Crush:glm-5.2

3-post-reboot-fixes.sh

@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+# Post-reboot validation fallout (2026-08-31). Run with sudo, once:
+#   sudo ~/optimize/3-post-reboot-fixes.sh
+# 1. Installs ethtool + enables virtio multiqueue (host side now offers
+#    4 queues on ens18, 2 on ens19; the guest defaults to 1 until told).
+# 2. Installs the gateway ensure-up unit (prod boot race on the tailscale-IP
+#    port bind + live-restore endpoint loss, both lanes; idempotent).
+set -euo pipefail
+[ "$(id -u)" = 0 ] || { echo "run with sudo"; exit 1; }
+cd "$(dirname "$0")"
+export DEBIAN_FRONTEND=noninteractive
+
+apt-get update -qq
+apt-get install -y -qq ethtool
+
+install -m 0755 staged/ukrrs-gateway-ensure.sh  /usr/local/sbin/
+install -m 0644 staged/systemd/ukrrs-gateway-ensure.service  /etc/systemd/system/
+install -m 0644 staged/systemd/ukrrs-net-multiqueue.service  /etc/systemd/system/
+systemctl daemon-reload
+systemctl enable --now ukrrs-net-multiqueue.service
+systemctl enable --now ukrrs-gateway-ensure.service
+
+echo; echo "== verify =="
+ethtool -l ens18
+ethtool -l ens19
+timeout 5 bash -c '</dev/tcp/100.101.187.119/4000' 2>/dev/null && echo "gateway prod: serving on :4000"