10. Mini-kalendarz z wydarzeniami

// Generowanie dni miesiąca
function getDaysInMonth(year, month) {
  const firstDay = new Date(year, month, 1);
  const lastDay = new Date(year, month + 1, 0);
  const startOffset = (firstDay.getDay() + 6) % 7; // Pon = 0
  const days = [];
  for (let i = 0; i < startOffset; i++) days.push(null);
  for (let d = 1; d <= lastDay.getDate(); d++) {
    days.push(new Date(year, month, d));
  }
  return days;
}