test: drift-check diverged probe

[joshua-temple]

Mutates a generated workflow so the drift gate must fail. Not for merge.

[github-actions]

Workflow drift detected

The generated workflows are out of sync with the manifest.

To fix, run and commit the result:

cascade generate-workflow --config .github/manifest.yaml --force

cascade verify output

~ .github/workflows/orchestrate.yaml

1 file(s) drifted. Run `cascade generate-workflow` and commit the result.
Error: workflow drift detected
workflow drift detected