/** Median of numeric samples; empty input yields null (not zero). */
export const medianOf = (values: ReadonlyArray<number>): number | null => {
  if (values.length === 0) return null
  const sorted = [...values].sort((a, b) => a - b)
  const middle = Math.floor(sorted.length / 2)
  return sorted.length % 2 === 0 ? (sorted[middle - 1] + sorted[middle]) / 2 : sorted[middle]
}