Preflop equity matrix

buildPreflopEquityMatrix returns a Float64Array of length 169 * 169 (row-major). Each cell is Monte Carlo equity for canonical preflop hands with disjoint suits.

const poker = require('poker-calculations');
const m = poker.buildPreflopEquityMatrix({ iterations: 5000, seed: 42, threads: 4 });

Options match PreflopMatrixOptions: iterations, seed, and threads (parallel C++ workers inside the native call).

For i ≠ j, M[j,i] = 1 - M[i,j] (row-major indexing). See Numerical semantics.