ci: publish cookbook as OCI artifact

[damacus]

Summary

Publish this cookbook as an OCI artifact and SPDX attachment in GHCR when the shared release workflow creates a release. The cookbook now follows the maintained Sous Chefs shared workflows and actions from main.

Verification

• actionlint .github/workflows/*.yml

The OCI publishing job uses the existing release secrets and is non-blocking, so Supermarket publication remains independent if GHCR publication fails.

[github-actions]

Slowest examples

Top 10 slowest examples (1.27 seconds, 35.94% of total time)

Example	Description	Time in seconds
spec/install_spec.rb:15	elasticsearch_install type repository (default) is expected to install elasticsearch_install_repository "ElasticSearch 8.19.12"	0.17062
spec/install_spec.rb:37	elasticsearch_install type tarball raises error raises an error	0.16251
spec/install_repository_spec.rb:18	elasticsearch_install_repository action :install on debian is expected to install package "elasticsearch"	0.15262
spec/install_package_spec.rb:63	elasticsearch_install_package action :remove is expected to remove package "/tmp/d20260915-3010-8pj8md/elasticsearch-8.19.12-amd64.deb"	0.14544
spec/install_package_spec.rb:51	elasticsearch_install_package action :install on suse is expected to install package "elasticsearch-8.19.12-x86_64.rpm"	0.14256
spec/install_package_spec.rb:17	elasticsearch_install_package action :install on debian is expected to create remote_file "/tmp/d20260915-3010-49aj9p/elasticsearch-8.19.12-amd64.deb"	0.12432
spec/user_spec.rb:42	elasticsearch_user action :remove is expected to remove group "elasticsearch"	0.09539
spec/install_repository_spec.rb:17	elasticsearch_install_repository action :install on debian is expected to add apt_repository "elastic-8.x"	0.09408
spec/install_spec.rb:26	elasticsearch_install type package is expected to install elasticsearch_install_package "ElasticSearch 8.19.12"	0.09261
spec/service_spec.rb:51	elasticsearch_service with default configuration creates systemd unit without restart policy	0.09204