Why

These workflows currently hard-code the codex runner group and custom runner labels. That makes the same workflow definitions less portable across repository copies or renamed repos, even though the runner fleet follows the repository name scheme. Template the runner identities from the repository name so openai/codex still resolves to the existing codex-* runners while other repos can use their own <repo>-* runner names.

What Changed

• Replaced custom runner group values such as codex-runners with ${{ github.event.repository.name }}-runners.
• Replaced custom runner labels such as codex-linux-x64 and codex-windows-arm64 with ${{ github.event.repository.name }}-....
• Covered direct runs-on objects, matrix runs_on entries, reusable workflow runner inputs, and release runner labels.

Verification

• Parsed all .github/workflows/*.yml files as YAML with Ruby.
• Searched .github/workflows to confirm no hardcoded runner-field codex-runners or codex-* labels remain.