feat(rank6): node-exporter renders from a template; guard chain is one snippet

- service-map render node-exporter-unit --host H: the MIRROR pair comment
  ('keep this file in step') becomes a template. Per-host title, LAN
  address from the hosts map, port from the node-<host> scrape job. Both
  tracked quadlets are now rendered artifacts; check_drift gates them.
- dankclaw/Caddyfile: the nine verbatim Anubis pre-auth chains
  (reverse_proxy anubis:8923 + X-Real-Ip) collapse into the (guarded)
  named snippet; guarded vhosts are 'import guarded'. Validated with real
  caddy 2.11.7 (import resolution clean; the stock image stops at the
  porkbun module and the git basicauth placeholder, as designed).
- vhost-scoped guard greps (authentik, homepage_caddy, marreta_quadlet)
  now pin 'import guarded' in the vhost block.
- Service Inventory + Authentik docs carry the new laws.

dankserver/observability/quadlet/node-exporter.container

@@ -1,34 +1,32 @@
-# Quadlet unit: node-exporter (rootless, boot-persistent) — DANKSERVER.
+# Quadlet unit: node-exporter (rootless, boot-persistent) — RENDERED ARTIFACT.
+# Regenerate: python3 scripts/service-map.py render node-exporter-unit --host dankserver
+# Source: shared/services.yml (entry node-exporter) + this template.
 #
 # Install path on dankserver: ~/.config/containers/systemd/node-exporter.container
 # Unit name: node-exporter.service (container name: node-exporter)
 #
-# WHY THIS FILE EXISTS. Until 2026-09-16 the Dankserver node-exporter ran only
-# from `dankserver/compose.yaml` (the "Observability" block, `restart:
-# unless-stopped`). Rootless Podman does not restart bare containers after the
-# explicit stop that shutdown performs, so it died at a reboot and stayed dead:
-# `podman ps -a` showed it `Exited (143)` and Prometheus' `node-dankserver` job
-# had been scraping nothing since. The compose entry also bound the default
-# wildcard address, which is the unauthenticated-metrics-API-on-every-interface
-# posture that was already removed on Dankclaw. This unit replaces both: one
-# owner per container name (the compose service is deleted), explicit listen
-# addresses, and a generator-provided boot path.
+# Host metrics source for Prometheus. Replaces the compose service of the same
+# name (the "Observability" block): Dankclaw moved to this quadlet on
+# 2026-09-11, Dankserver on 2026-09-16 — its compose-only copy died at a reboot
+# and stayed dead (rootless Podman does not restart bare containers after the
+# explicit stop shutdown performs), dead for a day and a half before anyone
+# noticed. One owner per container name; no compose file remains anywhere.
 #
-# HOST NAMESPACE. Networking and PID in the host's namespaces: the collectors
-# report the host's own interfaces, connections, processes and cgroups. The
-# host's /proc, /sys and / are mounted read-only under /host and /rootfs, and
-# node_exporter writes nothing.
+# HOST NAMESPACE. It must run in the host network namespace to report the
+# host's own interfaces/connections, and --pid=host for the processes and
+# cgroups collectors. "localhost" inside the container is therefore the host's
+# loopback, which is what the homepage status timer probes.
 #
-# LISTEN ADDRESSES. Exactly two:
-#   - 127.0.0.1:9100   for host-local probes
-#   - 192.168.0.235:9100 for Prometheus, which scrapes this host from Dankclaw
-#     (shared/prometheus/prometheus.yml, job "node-dankserver"). It cannot use
-#     loopback across hosts, and node_exporter has no authentication, so the
-#     wildcard bind stays off the table. This is the same deliberate LAN
-#     listener posture the observability runbook documents.
+# LISTEN ADDRESSES. Exactly two: loopback for the homepage status probe, and
+# the LAN address, because Prometheus — which runs in a container on
+# dankclaw_default — scrapes http://192.168.0.235:9100/metrics
+# (shared/prometheus/prometheus.yml, job "node-dankserver"). node_exporter has no
+# authentication, so the wildcard bind stays off the table; this is the
+# pairing that removes the unauthenticated observability surface on every
+# host, and both consumers are accounted for.
 #
-# MIRROR. Keep this file in step with dankclaw/observability/quadlet/
-# node-exporter.container; only the Description and the LAN address differ.
+# MOUNTS. The container reads the host's /proc, /sys and / as /host/*
+# read-only and is pointed at them with --path.*; it writes nothing anywhere.
 
 [Unit]
 Description=Prometheus node exporter (Dankserver host metrics)