feat(dns): publish public names as proxied CNAMEs to the Cloudflare Tunnel

Gateway target -> fc81938b-...cfargotunnel.com, --cloudflare-proxied globally,
L4 service publishers (unifi, crafty-mc) pinned DNS-only, Plex web UI and
Headlamp disowned (LAN/VPN-only). L0 internal-services-publish-no-public-dns
gains assertion (9) tying the Gateway target to the tunnel UUID, requiring
cloudflare-proxied=false on every service-source publisher, and keeping the
tunnel's 404 list and the unpublished set consistent. L2 dns-exposure fixture
opts out of proxying.

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

platform/externaldns/helmrelease.yaml

@@ -107,29 +107,47 @@ spec:
     # what this instance can see or own; per-resource exclusion only ever REMOVES an object from
     # this instance's view, so it cannot make prod capable of deleting a record it does not own.
     # ---------------------------------------------------------------------------------------------
-    # THE PUBLIC TARGET — DECIDED 2026-10-03 (operator): every Gateway-published name goes public
+    # THE PUBLIC TARGET — THE CLOUDFLARE TUNNEL, PROXIED (2026-11-08; supersedes 2026-10-03)
     #
-    # Until 2026-10-03 every gateway-sourced record answered with the Gateway VIP (192.168.2.20,
-    # RFC1918), so nothing published here was reachable from the internet. Two facts constrained the
-    # fix, and both still hold:
-    #   * `external-dns.alpha.kubernetes.io/target` is read in v0.21.0's gateway-httproute source ONLY
-    #     from the GATEWAY (source/gateway.go: `overrides: annotations.TargetsFromTargetAnnotation(
-    #     gw.Annotations)`) and from a ListenerSet listener — NEVER from an HTTPRoute. A target on the
-    #     shared Gateway therefore moves EVERY gateway-sourced record at once.
-    #   * The home WAN IP is residential and can change, so a literal IP in Git would rot.
+    # History: until 2026-10-03 every gateway-sourced record answered the Gateway VIP (RFC1918);
+    # from 2026-10-03 they were CNAMEs to `wan.${BASE_DOMAIN}` (DNS-only, the home WAN IP, with the
+    # router forwarding tcp/80+443 to the VIP). Both published an origin address of ours. Now:
+    #   * platform/gateway/gateway.yaml sets `target: <tunnel-uuid>.cfargotunnel.com` on the shared
+    #     Gateway. `target` is read in v0.23.0's gateway-httproute source ONLY from the GATEWAY
+    #     (source/gateway.go: `overrides: annotations.TargetsFromTargetAnnotation(gw.Annotations)`),
+    #     never from an HTTPRoute, so this one value moves every gateway-sourced record at once.
+    #   * `--cloudflare-proxied` below orange-clouds every record by default. It is GLOBAL because
+    #     that is the only practical lever: v0.23.0 reads the per-object `cloudflare-proxied`
+    #     annotation from the ROUTE (or Service), never the Gateway (source/gateway.go:
+    #     `annotations.ProviderSpecificAnnotations(annots)` with `annots := meta.Annotations` of the
+    #     route), so a Gateway-level opt-in does not exist. A CNAME to cfargotunnel.com MUST be
+    #     proxied — DNS-only it resolves to nothing routable — so "proxied by default" is the right
+    #     default for this zone's gateway names.
+    #   * The provider honours a per-object `"false"` over the global default (provider/cloudflare
+    #     shouldBeProxied: ParseBool of the annotation overrides proxiedByDefault). The key it reads
+    #     is `<annotationPrefix>cloudflare-proxied` (annotations.SetAnnotationPrefix re-derives
+    #     CloudflarePrefix), i.e. `external-dns.alpha.kubernetes.io/cloudflare-proxied` here.
+    #
+    # THE `service` SOURCE MUST OPT OUT. The L4 LoadBalancers (crafty-mc, unifi) publish an A record
+    # at their own LB VIP; Cloudflare's proxy is HTTP(S)-only, so a proxied A for a game or UniFi
+    # inform port is broken by construction. Each carries `cloudflare-proxied: "false"` and stays
+    # DNS-only, exactly as before this change. conformance/tests/l0-static/
+    # internal-services-publish-no-public-dns (assertion 9b) FAILS on any `service`-source publisher
+    # without it, so a new L4 Service cannot silently become a proxied record.
     #
-    # The operator's answers: (a) yes, ALL of them — the five `exposure: public` apps AND the admin
-    # UIs (auth, crafty, grafana, headlamp, the apex), which sit behind Keycloak / oauth2-proxy;
-    # (b) the address is kept current IN-CLUSTER. Implementation:
-    #   * platform/gateway/gateway.yaml sets `target: wan.${BASE_DOMAIN}` on the shared Gateway, so
-    #     each published name becomes a CNAME to that one hostname;
-    #   * platform/externaldns/ddns.yaml (favonia/cloudflare-ddns) keeps `wan.${BASE_DOMAIN}` an A
-    #     record at the current WAN IP. That record has no external-dns TXT registry entry, so this
-    #     instance never owns or garbage-collects it.
     # Internal services are unchanged: their routes carry `controller: none` (above), which is
-    # checked BEFORE the target is read, so they still publish nothing. The `service` source (the L4
-    # LoadBalancers crafty-mc, unifi) does not read the Gateway's annotation and still publishes its
-    # LB VIP. Whether those should go public is a separate, still-open question.
+    # checked BEFORE the target is read, so they still publish nothing. Plex's web UI and Headlamp
+    # joined that set on 2026-11-08 (operator: LAN/VPN-only). `wan.${BASE_DOMAIN}` (ddns.yaml) has no
+    # external-dns TXT registry entry and is untouched; it now serves only WireGuard udp/51820.
+    #
+    # THE RISK THIS ADDS, AND WHAT GUARDS IT. If the annotation prefix ever stops being honoured
+    # again (the 2026-11-07 v0.23.0 incident), `target` is ignored and every name falls back to the
+    # Gateway's own address — and with this flag it would be published as a PROXIED A record at
+    # ${GATEWAY_VIP} (RFC1918; Cloudflare 1003/522s for every public name) while `controller: none`
+    # is also ignored and internal names publish. Assertion (8) of the L0 check above ties the
+    # prefix this tree writes to `values.annotationPrefix`; (8b) forbids overriding it here.
+    extraArgs:
+      - --cloudflare-proxied
     # ---------------------------------------------------------------------------------------------
     # CROSS-CLUSTER DNS OWNERSHIP. Read before changing either knob below.
     #