fix(external-dns): remove invalid --target flag, move to per-resource annotation

ExternalDNS v0.15.1 does not support --target as a CLI flag.
Remove the extraArgs stanza from external-dns-cloudflare values.yaml
and instead add the target annotation directly on the CouchDB ingress:
  external-dns.alpha.kubernetes.io/target: ingress.mk-labs.cloud

This achieves the same result (Cloudflare CNAME -> ingress.mk-labs.cloud)
without crashing the controller.

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

@@ -38,10 +38,6 @@ sources:
 # 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=ingress.mk-labs.cloud
-
 # Log level
 logLevel: info