v1.20.0

Added — a back-reference beside every anchored rule (W2137)

Canon entry edit-site-back-reference requires prose beside every governed-rule statement naming the canon by path and the entry id, and the drift check implements it as a property, so an anchor standing alone is reported rather than passing. Four paragraphs close this extension's five anchored statements: the verdict-note pair in extensions/subagent-dispatch/agents/stride-task-reviewer.md — this repository's reviewer is nested there rather than at a top-level agents/ path — and the decision matrix, its ordering, the review ceiling and the reason_code vocabulary in skills/stride-workflow/SKILL.md.

Each says rewording is free and changing the claim is not, and closes by naming what the checker actually inspects: the anchor, never the sentence. Its decision-matrix-authority and row-precedence anchors are three lines apart — the tightest pair in the fleet — so one paragraph names both and says which prose answers to which.