Phase 57: bgkf-vs-public alignment check (3 sign flips; better than purge; vrel the one coherent cross-fleet signal)

EXPERIMENTS.md

@@ -3137,3 +3137,15 @@ scales with fleet size as designed). NEW DENOMINATION: per-test-fleet cost,
 never cross-compare with the full-fleet instruments (1972.0 purge / 1661.7
 self-fit). Harness runtime 22s - cheap enough to run per candidate without
 triage subsets.
+
+Phase 57 alignment check vs recorded public scores (user request; pooling
+arm killed mid-run): champion 352.0 reference; cert-first bgkf -7.3+/-4.3 vs
+public +43 (flip); frontier -5.3+/-7.4 vs public +216 (flip, but far less
+fooled than the purge's -342, and it reproduces the public swap-count-drop
+direction); alpha 1.5 -28.8+/-13.6 at swaps 3.15 vs public +527 (flip -
+still rewards appetite; note 65W/118L, the count-asymmetry signature).
+Verdict: better than the purge, still sign-flips all three public killers -
+fleet-composition facts (uncatchable public tail, train-absent ghosts) are
+invisible to ANY local split. The structural shipping bar (flat swaps per
+cell, no label-process exploits) remains the only local defense. One
+coherent cross-fleet signal: vrel -13.4+/-7.9, 104W/61L, swaps flat.