[Chore]: publish the helm chart to OCI #193
Description
Summary
Publish the Helm chart to OCI registry (ghcr.io) for easier installation and GitOps compatibility.
Motivation
- Direct install:
helm install oci://ghcr.io/stacklok/toolhive-cloud-ui/toolhive-cloud-ui - Native ArgoCD/Flux support
- Cosign signing for supply chain security