Lead agent: verify small delta fixes yourself instead of re-running full reviews

When a doc or code change goes through repeated independent reviews, each fresh reviewer keeps finding new Lows, so the loop doesn't converge on its own. A practical rule: run full independent reviews until nothing is Blocking or High, then have the author apply the remaining mechanical fixes, and have the lead check that small delta directly (git diff --stat old new, plus a grep of the added lines for banned terms and the specific wording asked for). Also, sub-agent reviewers spawned by another sub-agent may hand their reports back to the top-level session instead of the agent that spawned them, so the lead should forward them.