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>

internal/config/config_test.go

@@ -3,6 +3,7 @@ package config
 import (
 	"os"
 	"path/filepath"
+	"reflect"
 	"testing"
 	"time"
 )
@@ -18,7 +19,7 @@ func TestExampleParses(t *testing.T) {
 	if c.BIND.ZoneDir != d.BIND.ZoneDir || time.Duration(c.Session.IdleTimeout) != 2*time.Hour || c.Listen[0] != "127.0.0.1:8053" {
 		t.Errorf("example differs from defaults: %+v", c)
 	}
-	if c.ACME != d.ACME || c.ACME.HTTPReq.Enabled || !c.ACME.HTTPReq.RequireHTTPS {
+	if !reflect.DeepEqual(c.ACME, d.ACME) || !reflect.DeepEqual(c.Certificates, d.Certificates) || c.ACME.HTTPReq.Enabled || !c.ACME.HTTPReq.RequireHTTPS {
 		t.Errorf("acme = %+v, want the defaults %+v", c.ACME, d.ACME)
 	}
 }