Honor custom colors in binary curves

[uriahf]

Summary

• make binary ROC, precision-recall, lift, gains, and decision create_* functions honor color_values
• preserve R behavior where a single model remains black
• recolor group-specific reference traces consistently with their model/population
• validate that a custom palette has enough colors
• add end-to-end regression tests across the binary curve family

Scope

No statistical calculations, cutoff semantics, schemas, or runtime dependencies are changed.

Audit classification

Correctness/API bug: binary public curve creators accepted color_values but silently rendered the built-in palette instead.

[github-actions]

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2026-08-20 11:03 UTC