fix(external-dns): exclude internal records from Cloudflare, add opt-in filter, set targets

- external-dns-cloudflare: add excludeDomains: [local.mk-labs.cloud] to stop
  internal subdomain records from leaking to Cloudflare
- external-dns-cloudflare: replace hostname annotationFilter with opt-in model
  (external-dns.alpha.kubernetes.io/public=true) so only explicitly tagged
  services get public Cloudflare records
- external-dns-cloudflare: add extraArgs --target=lb.mk-labs.cloud
- external-dns (Technitium/rfc2136): add extraArgs
  --target=lightning-lane.local.mk-labs.cloud for internal records
- couchdb: add external-dns.alpha.kubernetes.io/public: 'true' annotation —
  first service to opt in to public DNS; will create communicore.mk-labs.cloud
  pointing to lb.mk-labs.cloud via Cloudflare ExternalDNS

URGENT: Cloudflare was creating records for local.mk-labs.cloud hosts.
Ryan: manually delete any *.local.mk-labs.cloud records currently in Cloudflare
(look for communicore.local.mk-labs.cloud and any other local.* entries).

cluster/platform/external-dns-cloudflare/values.yaml

@@ -23,14 +23,24 @@ env:
 domainFilters:
   - mk-labs.cloud
 
+# Explicitly exclude internal subdomain — prevents local.mk-labs.cloud from
+# leaking into Cloudflare (domainFilters matches subdomains by default)
+excludeDomains:
+  - local.mk-labs.cloud
+
 # Sources: ingress and services
 sources:
   - ingress
   - service
 
-# Annotation to opt resources into public DNS management.
-# Use: external-dns.alpha.kubernetes.io/hostname: myservice.mk-labs.cloud
-annotationFilter: "external-dns.alpha.kubernetes.io/hostname"
+# Opt-in model: only process resources explicitly annotated for public DNS.
+# Add annotation external-dns.alpha.kubernetes.io/public: "true" to any
+# ingress/service that should get a public Cloudflare record.
+annotationFilter: "external-dns.alpha.kubernetes.io/public=true"
+
+# Override the target for all Cloudflare-managed records to the public LB CNAME.
+extraArgs:
+  - --target=lb.mk-labs.cloud
 
 # Log level
 logLevel: info