sbwadjust - Stable Balancing Weights for Covariate Adjustment in Trials

Covariate adjustment for randomized trials using stable balancing weights (SBW), as proposed by Irish, Zubizarreta, and Luedtke (2026) <doi:10.48550/arXiv.2609.01638>. sbw_weights() fits exact-balance SBW for a two-arm study by a closed-form solve with a nonnegative quadratic-programming fallback; sbw_estimate() computes a closed menu of treatment-effect estimands (average treatment effect, relative risk, survival ratio, Mann-Whitney, quantile contrasts) from the fitted weights, with bootstrap confidence intervals.