item 21 McNemar scored: drop-bucket edge significant (2:6 p=0.0094, survives Bonferroni x4); overall A-vs-B ns; + session handoff, fig cleanup

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

results-loop/PROTOCOL_UNIFIED.md

@@ -513,8 +513,14 @@ consistent, specific signature: DROP items (unreachable by the base
 model even with full CoT at labeling) — A beats B by +9 and +14 points
 there in the two cells. Interpretation: scratchpad supervision carries
 the bulk; the carry chain specifically extends reach into previously
-unreachable problems. McNemar p-values pending (mcnemar_carrycot.py
-ready; classifier-blocked at scoring time). (c) CONFIRMED: easy damage
+unreachable problems. McNemar (scored 2026-07-16 morning): overall
+A-vs-B not significant in either cell (2:2 discordants 34-23 p=0.185;
+2:6 33-26 p=0.435), but the pre-identified drop-bucket signature IS:
+2:6 drop discordants 20-6, exact McNemar p=0.0094 (survives
+Bonferroni x4 = 0.038); 2:2 drop 16-7, p=0.093 (same direction,
+marginal). Verdict: the whiteboard's edge is real and specific to
+extending reach into drop items, not a general lift over matched
+supervision. (c) CONFIRMED: easy damage
 much reduced vs answer-only carry (83->72-83 vs 83->45). Ladder gate:
 technically met at p=2; decision on stage B/A2/E2-N deferred to the
 morning review with the p-values in hand — the drop-bucket signature,