Reference a remote OCI artifact as a Kustomize base

Steps

1. Note that native Kustomize resources/bases fields do not support oci:// references in current stable releases — pulling OCI-packaged Kustomize manifests directly is an open, unmerged feature request (kubernetes-sigs/kustomize issue #5134, with implementation PR #5147 still in progress), so writing oci://... under resources: or bases: will not work as of this writing.
2. For remote bases that are actually supported, reference a Git repository (with an optional ?ref=<tag> and a double-slash path segment) or a plain HTTPS URL under resources:, e.g. resources: - https://github.com/org/repo//path/to/base?ref=v1.2.3.
3. If the manifests you need are only published as an OCI artifact (e.g. pushed with Flux's flux push artifact), pull and unpack it out-of-band first — e.g. flux pull artifact oci://ghcr.io/org/repo:tag --output ./vendor/base (or an equivalent oras/crane pull) — then reference the resulting local directory as a normal Kustomize base under resources:.
4. If you're already running Flux CD, prefer its native OCIRepository + Kustomization custom resources, which fetch the OCI artifact and run kustomize build against it server-side, rather than trying to make the kustomize CLI itself understand oci://.
5. Track kubernetes-sigs/kustomize issue #5134 for native OCI support landing in a future release, and re-test with kustomize version before removing the vendor/pull workaround.