Changes in version 0.1.0 (2026-09-12) - Initial packaged release of kernel-weighted Cox regression (chestr) for exploring treatment effect heterogeneity on a biomarker grid. - Implements Kish effective-sample-size (ESS) events-per-df safeguard (min_events_per_df, default 10). Grid points below the threshold are skipped with NA coefficients and flagged via reliable. - Exported API: chestr(), plot.chestr() / plot(), chestr_test(). - Weighting methods: "distance" (default), "square_distance", "legacy". - Global permutation test of constant treatment effect over biomarker space (T_L2, T_MAX) via chestr_test(). - Vignette chestr-workflow demonstrates the global Cox → chestr → plot workflow (and optional permutation test) on simulated survival data.