Surfaced during live acceptance testing of #843 (PR #956). After aicr bundle --deployer argocd-helm --output oci://localhost:5500/aicr/eks-training:<tag> --plain-http reports a successful push, helm upgrade --install against the same registry returns:

$ helm upgrade --install aicr-test-stack oci://localhost:5500/aicr/eks-training \
    --version 5bc50950-argocd-helm-oci \
    --namespace argocd \
    --plain-http
Release "aicr-test-stack" does not exist. Installing it now.
Error: unable to locate any tags in provided repository: oci://localhost:5500/aicr/eks-training

The bundler's pkg/oci/push.go uses ociv1.MediaTypeImageLayerGzip for the layer and the custom application/vnd.nvidia.aicr.artifact for the manifest config. Helm OCI expects:

• Chart layer mediaType: application/vnd.cncf.helm.chart.content.v1.tar+gzip
• Manifest config mediaType: application/vnd.cncf.helm.config.v1+json
• Tag enumeration via /v2/<name>/tags/list (standard OCI distribution API)

Hypotheses (need verification):

1. Layer mediaType mismatch: helm OCI rejects artifacts whose layer mediaType isn't helm.chart.content.v1.tar+gzip. AICR pushes oci.image.layer.v1.tar+gzip — fine for Argo CD's raw OCI source but possibly not for helm.
2. Config mediaType mismatch: application/vnd.nvidia.aicr.artifact for the manifest config is the artifactType; helm needs the Helm-specific config schema (Chart.yaml-derived JSON metadata).
3. Missing helm annotation (oci.opencontainers.image.title etc.) on the manifest — helm's discovery may need OCI annotations identifying the artifact as a chart.

Reproduction:

unset GITLAB_TOKEN && make build
make kwok-cluster   # any single-node Kind cluster; the registry is local
bash kwok/scripts/install-infra.sh
$AICR bundle --deployer argocd-helm --output oci://localhost:5500/aicr/test:v1 --plain-http \
    --recipe <(aicr recipe --service eks --intent training)
helm upgrade --install test oci://localhost:5500/aicr/test --version v1 --plain-http -n argocd
# Error: unable to locate any tags in provided repository

Likely fix area: pkg/oci/push.go::PackArtifact — when --deployer argocd-helm, push with Helm-compatible mediaTypes/annotations so the artifact is discoverable by both Helm OCI and Argo CD (Argo CD v3.x's OCI Helm chart source already accepts helm.chart.content.v1.tar+gzip per its docs).

PR #956 (draft) ships helm + argocd-helm-oci wiring; argocd-helm-oci is blocked on this issue.