* feat: make stale PR workflow fork-aware with workflow_dispatch support Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com> * fix: add null check for pr.head.repo in stale PR workflow When a fork is deleted after a PR is created, pr.head.repo can be null (documented GitHub API behavior). This would cause a TypeError when accessing properties like fork, full_name, or clone_url. Added a null check that fails gracefully with a clear error message when the source repository has been deleted. Co-Authored-By: unknown <> --------- Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>