Use workflow_run pattern to enable the Cubic AI to Devin review workflow
for PRs from external forks. The pull_request_review event doesn't have
access to secrets when triggered from forks, so we split into two workflows:
1. cubic-devin-review-trigger.yml - Lightweight workflow that triggers on
pull_request_review and saves the review context as an artifact
2. cubic-devin-review.yml - Main workflow that triggers on workflow_run,
downloads the artifact, and processes it with full permissions/secrets
This follows the same pattern used by on-changes-requested.yml and re-draft.yml.
Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
