bind-internal: add ceph.unkin.net authoritative zone (#260)

## Why
The ceph/halb host (`ausyd1nxvm2069`) publishes `dashboard.ceph.unkin.net` via nsupdate to a dedicated `zone ceph.unkin.net.`, which `bind-authoritative` was not authoritative for (NOTZONE). This adds the zone so that record has a home.

## Changes
- Add `ceph.unkin.net` BindZone (primary, dynamicUpdate, updateKeyRef client-update) to bind-authoritative, matching the unkin.net/main.unkin.net pattern.

## Note — not the root cause of the 6 missing hosts
Log evidence (VictoriaLogs, dns-update-apply on 2069/2070) shows the actual failure is a **host-side bug in the puppet `dns-update` script**: `fqdn()` appends the zone even to records whose name is already fully-qualified (e.g. `au-syd1-pve.main.unkin.net.`, `cobbler.main.unkin.net.`), producing a `..` empty label → `invalid owner name: empty label` → the whole main.unkin.net update `send` fails (reverse PTR, sent first, still lands). That script fix (puppet-prod) is the real blocker; this zone is still needed so the ceph record does not hit NOTZONE afterward.

Reviewed-on: #260
Co-authored-by: Ben Vincent <ben@unkin.net>
Co-committed-by: Ben Vincent <ben@unkin.net>

apps/base/bind-internal/authoritative/zones.yaml

@@ -31,6 +31,22 @@ spec:
   dynamicUpdate: true
   updateKeyRef: client-update
 ---
+# ceph.unkin.net: the ceph host (ausyd1nxvm2069/halb) publishes
+# dashboard.ceph.unkin.net via nsupdate; puppet targets a dedicated
+# `zone ceph.unkin.net.`, so it must exist here or the update gets NOTZONE.
+apiVersion: bind.unkin.net/v1alpha1
+kind: BindZone
+metadata:
+  name: ceph-unkin-net
+  namespace: bind-internal
+spec:
+  clusterRef: bind-authoritative
+  zoneName: ceph.unkin.net
+  type: primary
+  defaultTTL: 600
+  dynamicUpdate: true
+  updateKeyRef: client-update
+---
 apiVersion: bind.unkin.net/v1alpha1
 kind: BindZone
 metadata: