Context

When PRs modify documentation in the docs/ directory, reviewers currently cannot easily preview the rendered documentation. This slows down the review process and makes it harder to catch formatting issues.

Acceptance Criteria

• When a PR modifies files in docs/, a CI job triggers automatically
• The job builds MkDocs documentation and deploys to Cloudflare Pages
• A comment is posted on the PR with the preview URL (https://pr-[number].hypershift.pages.dev)
• Preview is available until the branch is cleaned up

Implementation

Add CI configuration to openshift/release repository:

• Step-registry entries for build, deploy, and comment steps
• Test configuration in hypershift ci-operator config with run_if_changed: ^docs/

Cloudflare Pages credentials are already configured in hypershift-team ops vault.