Problem:
Too many "jobs" listed in the CI report.
Solution:
- Do the "ai-assisted" step in the "label" job. No need for them to be
separate.
- Also drop the "already labeled" check; `gh pr edit --add-label` is
idempotent.
- Note: AI-assisted PRs are now labeled only on the "opened" event,
which is fine.
dad084c394