Phase 58: definitive v5-vs-public coherence - zero false adoptions under the full protocol; faithful config reproduction matters (alpha stack reads n.s., approximations overstated misalignment)

EXPERIMENTS.md

@@ -3149,3 +3149,35 @@ 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.
+
+## Phase 58 - definitive local-vs-public coherence check on the v5 harness (deployment-faithful GroupKFold)
+
+All five publicly-measured configs reproduced AS SHIPPED (the alpha point as
+the true ALPHA_STATIC=1.5 + CLIFF_SCALE=2.2 stack driving the count through
+p42_sum; cert stacked on rank_score; pooling with time-masked own pairs;
+deployment-exact planner state incl. the gated floor; v5 baseline = 352.0,
+byte-identical to v3, floor confirmed inert):
+
+| config | local delta +/- SE | swaps | public delta | decision at the 2-sigma bar |
+|---|---|---|---|---|
+| alpha15+cliff22 | -15.4 +/- 16.8 | 4.18 | +527.3 | NOT adopted (0.9 sigma) - correct |
+| cert-first | -7.3 +/- 4.3 | 1.90 | +43.2 | NOT adopted (1.7 sigma) - correct |
+| pooling | +10.2 +/- 3.6 | 1.92 | +4.4 | rejected - SIGN AGREES |
+| frontier | -5.3 +/- 7.4 | 1.79 | +215.6 | NOT adopted (0.7 sigma) - correct |
+| (alpha15 solo, no public point) | -28.8 +/- 13.6 | 3.15 | - | 2.1 sigma BUT count-coupled (swaps +1.25) -> quarantine rule catches it |
+
+VERDICT: the v5 CV cannot reproduce public MAGNITUDES (ghosts and the
+uncatchable tail are absent from every local fleet - unfixable), but as a
+DECISION INSTRUMENT the full protocol - v5 harness + 2-sigma adoption bar +
+count-flat rule + no-label-process rule - makes the correct call on all five
+public measurements: zero false adoptions, one correct rejection with sign
+agreement. Notably the faithful reproduction itself mattered: alpha-solo
+reads a confident-looking -28.8 (2.1 sigma) while the actually-shipped
+alpha+cliff stack reads a statistical zero - earlier alignment checks that
+approximated configs overstated the misalignment. Residual sharpest risk:
+cert-class (1.7 sigma local win, public +43) - the label-process quarantine
+is what protects against it, not the harness.
+
+THE CV going forward: v5 building-GroupKFold (deployment-faithful held-out
+simulation, one instrument for public AND private - both are ~2x held-out
+fleets), used for ordering/model questions under the quarantine rules.