CalendarNavHeader
fun CalendarNavHeader(state: CalendarState, modifier: Modifier = Modifier, onTitleClick: () -> Unit? = null, previousMonthContentDescription: String = orreryString(OrreryString.PreviousMonth), nextMonthContentDescription: String = orreryString(OrreryString.NextMonth), showTodayButton: Boolean = false, today: YearMonth = currentYearMonth(), todayLabel: String = orreryString(OrreryString.Today), title: @Composable (YearMonth) -> Unit = { month ->
NavHeaderTitle(month, showDropdown = onTitleClick != null)
})
Month navigation header: previous/next buttons around an animated month/year title. Place it above a HorizontalCalendar sharing the same CalendarState; buttons disable at the state's month range bounds. When onTitleClick is set the title becomes clickable and shows a dropdown affordance — the hook for hosting MonthYearPicker.
With showTodayButton a compact todayLabel text button appears after the next-month chevron while the visible month differs from today (and today lies within the state's month range); clicking it animates the calendar back to today.