docs: review-anti-loop - #856

Closes work#246: docs/REVIEW.md gets the anti-loop rules (what makes a major, evidence first, verify checks only the must-fix list, two rounds then one PM decision), exactly foxnne's rules of 2026-10-24; reviewing rules are an agent rule, so foxnne's yes on card pr-856 (2026-10-26 19:01Z); macos/agy clean at 4034409, CI green; docs only (+17/-2).