feat(dns): PiHole answers an explicit LAN name list, not a zone wildcard

Public names are proxied CNAMEs to the Cloudflare Tunnel since PR #156 and
work from the LAN, so they should resolve publicly there too. Replace the
address=/${BASE_DOMAIN}/ wildcard with explicit entries: the LAN-only names
(derived from every controller:none HTTPRoute), gitea/nextcloud (off
Cloudflare's 100 MB / 100 s limits), keycloak/auth, and the L4 VIPs.

Add L0 check pihole-lan-names, mutation-tested. Correct docs that still
described public names as CNAME to wan. and the cloudflared entrypoint comment.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

schemas/renderer-contract.md

@@ -82,13 +82,10 @@ platform must render, and cites the requirement each mapping satisfies. Changing
     all seven the moment it is set. Per-resource exclusion has exactly the blast radius of the
     defect. The filter stays available as hardening once those seven are adjudicated — see
     `platform/externaldns/helmrelease.yaml` and the register in the L0 check.
-- `public` renders the record but the renderer does **not** yet set a target: the record still
-  resolves to the shared Gateway VIP, i.e. an RFC1918 address, so a `public` service is not in fact
-  publicly reachable. Fixing that is **not** a renderer change on v0.21.0 —
-  `source/gateway.go` reads `external-dns.alpha.kubernetes.io/target` only from the **Gateway** (and
-  a ListenerSet), never from an HTTPRoute, so a per-service target override is not expressible while
-  the public services share the `shared` Gateway. The open decision is recorded in
-  `platform/externaldns/helmrelease.yaml`.
+- `public` renders the record but the renderer does **not** set a target: external-dns reads
+  `external-dns.alpha.kubernetes.io/target` only from the **Gateway** (and a ListenerSet), never from
+  an HTTPRoute, so the target is set once, on the `shared` Gateway — since 2026-11-08 the Cloudflare
+  Tunnel, proxied (`platform/gateway/gateway.yaml`, `platform/externaldns/README.md`).
 - Exposure does **not** relax east-west default-deny (docs/09 §"Interaction with default-deny").
 - **Requirements:** R-DNS-02/03 (docs/09), R-NET-04 (docs/03).
 
@@ -323,8 +320,9 @@ R-OBS-01 (the SLI must follow the rendered kind).
   `public` service**. An `internal` service's route is rendered with ExternalDNS's controller
   annotation set to `none`, which removes it from ExternalDNS's view entirely (see §`exposure`), so
   its `<host>` exists **only** in the internal split-horizon answer PiHole serves, never in the
-  public zone. A `public` record's TARGET is still the Gateway VIP, not a routable address — open
-  operator decision, see §`exposure`.
+  public zone. A `public` record's TARGET is the Cloudflare Tunnel (a proxied CNAME, from the
+  shared Gateway's target annotation; `platform/externaldns/README.md`), and a `public` name is
+  not listed in PiHole unless it must stay on the LAN path.
 - The `host` pattern is enforced to `<label>.home.keithjackson.dev` by the schema.
 - **Requirements:** **R-TLS-01/02/03** (docs/08), **R-DNS-01/02/03** (docs/09).