The new PR-maintenance workflows were cancelling queued work, failing model routing before repair began, and silently misclassifying rebase conflicts as changed heads.

This first recovery slice preserves queued runs, selects catalog-supported GPT-5.4 for repair and safety review, and classifies failed subprocesses from stderr. It also records the approved design for the subsequent per-PR coordinator and repair worker.

### Recovered flow


Validation: 18 maintenance tests pass, including three regressions that failed before the fix; `bun run ci`, `bun run types`, and strict gh-aw compilation pass. Live model access still needs a post-deployment smoke run.

Per-PR scheduling, labels, automatic conflict repair, and stack handling are subsequent slices. This PR does not claim to deliver the full readiness workflow.