pm-dispatch(contract-review): the lane reviews its own PRs, triage takes only an owed review nobody claims (drafts included); one Contract-review-claim line per head; an in-repo owed-review list

pm-dispatch(contract-review): the lane reviews its own PRs, triage takes only an owed review nobody claims (drafts included); one Contract-review-claim line per head; an in-repo owed-review list #15045