refactor(cert-manager): use cloudflare-token secret name

Change ClusterIssuer to use cloudflare-token secret (replicated by
Reflector from external-dns namespace) instead of cert-manager-secret.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: justgithubaccount

platform/infrastructure/networking/cert-manager/base/issuer-cluster.yaml

@@ -14,5 +14,5 @@ spec:
       - dns01:
           cloudflare:
             apiTokenSecretRef:
-              name: cert-manager-secret
+              name: cloudflare-token
               key: CLOUDFLARE_TOKEN