TLS certificates: Jarl obtains and renews them over ACME

Jarl is now an ACME client (lego's core, no DNS providers). It answers
DNS-01 challenges in a zone it serves, or through Porkbun's DNS API while
Porkbun serves the domain; "auto" decides from the domain's public name
servers at every renewal, and a CNAME on _acme-challenge is followed.
Certificates are used for jarld's HTTPS (served without a restart; each
port speaks HTTPS and plain HTTP, plain HTTP from loopback and trusted
proxies still served) and/or written for named's DNS over TLS/HTTPS, with
rndc reconfig on renewal. Renewal follows the CA's ARI window or two
thirds of the lifetime, with back-off. Certificates you renew yourself
can be used too. Certificates page and dashboard card, jarl cert,
/api/v1/certificates, Prometheus gauges, docs/certificates.md, and an
e2e section against Pebble.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/cli.md

@@ -397,6 +397,24 @@ jarl view update external --exposure public|private|auto
 
 See [exposure.md](exposure.md).
 
+## Certificates
+
+```sh
+jarl cert check --domain ns1.adbraun.lol             # where each challenge would go, and why
+jarl cert create ns1 --domain ns1.adbraun.lol --use web --use dns   # obtained at once; waits
+jarl cert create wild -d adbraun.lol -d '*.adbraun.lol' --use dns --key-type ec384
+jarl cert create own --cert-file /etc/ssl/ns1/fullchain.pem --key-file /etc/ssl/ns1/privkey.pem --use web
+jarl cert list
+jarl cert show ns1
+jarl cert issue ns1                                  # renew now (--no-wait to return at once)
+jarl cert update ns1 --challenge porkbun             # auto, jarl or porkbun
+jarl cert update ns1 --use dns                       # --use and --domain replace the list (--use none)
+jarl cert delete ns1
+jarl cert account                                    # the ACME account (set in jarl.yaml)
+```
+
+Administrators only. See [certificates.md](certificates.md).
+
 ## Views, ACLs, TSIG keys, options, settings
 
 ```sh