- Extend reviewer with 'spec' review type and spec review format template
- Add review_spec tool to triage agent for independent spec quality evaluation
- Implement APPROVE/REVISE/RETHINK loop with conversation rewind on RETHINK
- Add post-session gate to block tasks with unresolved REVISE verdicts from moving to todo
- Add tests for reviewer spec support and triage review loop (APPROVE, REVISE, RETHINK paths)