//! Project-wide structural and mathematical constants.
//!
//! This module is the single source of truth for compile-time parameters that are
//! shared across multiple features:
//! - [`entropy`]: Bandt–Pompe ordinal-pattern embedding (m=3, τ=1) and permutation
//! entropy normalization constant (ln(3!) = ln(6))
//! - [`math`]: Mathematical constants for volatility and entropy-based optimizations
//! (Garman-Klass coefficient, Hurst entropy-skip threshold)
//!
//! See `docs/adr/2026-06-03-bandt-pompe-embedding-constant.md`.