Block-layer unique top-1 0.20 sits at or below the 0.35 random expectation for 2.95 candidate ascendants, so H1-H4 had no signal to amplify. Not significant at n=20; recorded as "no positive signal", not "worse than chance". Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_0193vBv6w5MV2cifdTUu9H5P