cleanup-branches.yml has invalid YAML (missing steps: key), breaking lint:yaml for every PR #1074

Describe the bug

.github/workflows/cleanup-branches.yml, introduced in #1067, is missing the steps: key under the cleanup job. The env: mapping is immediately followed by a - name: Checkout repository list item with no steps: parent key, which is invalid YAML.

Because npm run lint:all runs spectral lint '**/*.{yml,yaml}' across the whole repo (not just changed files), this breaks the lint job - and therefore the required All Checks Passed status check - for every PR into develop, regardless of what the PR actually touches. Found while trying to get an unrelated PR (#1073) green.

To Reproduce

1. npm run lint:all on current develop
2. See parser errors at .github/workflows/cleanup-branches.yml:37-46 ("Bad indentation of a mapping entry", "Can not read a block mapping entry")

Expected behavior

cleanup-branches.yml parses as valid YAML and npm run lint:all passes.

Additional Context

Fix: insert steps: before the - name: Checkout repository line, at the same indentation as the job's other top-level keys (runs-on, env).

Definition of Ready (DoR)

• Bug is reproducible and clearly described
• Steps to reproduce written
• Linked to existing issues/PRs (if any)
• Ready for triage

Definition of Done (DoD)

• Bug confirmed and reproducible
• Fix implemented and verified
• Documentation updated (if needed)
• Changelog entry prepared for PR (CHANGELOG.md)
• Linked issue closed