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 (1.34 seconds, 26.43% of total time)

Example	Description	Time in seconds
spec/test/installation_package_spec.rb:173	test::installation_package Oracle 8: testing default action, default properties installs docker	0.18344
spec/test/container_spec.rb:957	test::container testing GPU support creates a container with GPU support	0.17057
spec/test/installation_package_spec.rb:106	test::installation_package RHEL (s390x): testing default action, default properties is expected to create yum_repository "docker"	0.168
spec/libraries/container_spec.rb:72	docker_container creates a docker container with default options is expected to create docker_container "hello_world"	0.15364
spec/libraries/container_spec.rb:471	docker_container creates a docker container with GPU support configures nvidia GPU support	0.14438
spec/libraries/container_networks_spec.rb:28	docker_container gets ip_address_from_container_networks when docker API < 1.21 gets ip_address as nil	0.12412
spec/test/image_spec.rb:22	test::image testing default action, default properties pulls docker_image[hello-world]	0.11016
spec/test/service_spec.rb:75	test::service creates docker_service[default]	0.10049
spec/test/container_spec.rb:733	test::container runs execute[change_network_mode]	0.09653
spec/test/service_spec.rb:187	test::service containerd does not exist creates docker_service[default]	0.09494