The pulse-chart package in GHCR currently requires authentication for pulls
because it defaults to private visibility. This affects all users trying to
install via `helm install oci://ghcr.io/rcourtman/pulse-chart`.
This commit adds a workflow step to automatically set the package to public
after each push, enabling anonymous pulls without requiring `helm registry login`.
Note: The existing package will need one-time manual configuration via GitHub
web UI until the next release triggers this workflow.
Related to discussion #686
The publish-helm-chart workflow was failing with 403 errors when attempting
to upload Helm chart assets to GitHub releases. This was caused by the workflow
having only 'contents: read' permission. Changed to 'contents: write' to allow
the 'gh release upload' command to succeed.
