export function mostFrequentChar(text: string): string {
  const counts: Record<string, number> = {}

  for (const c of text) {
    counts[c] = (counts[c] ?? 0) + 1
  }

  return Object.entries(counts)
    .sort(
      ([charA, countA], [charB, countB]) => 
        countB - countA || charA.localeCompare(charB)
    )[0][0]
}