[V2] Allow outside month selection in pickers

[Arisablad]

https://github.com/heroui-inc/heroui/blob/v2/packages/components/calendar/src/calendar-cell.tsx

export interface CalendarCellProps extends HTMLHeroUIProps<"td">, AriaCalendarCellProps {
  state: CalendarState | RangeCalendarState;
  isPickerVisible?: boolean;
  slots?: CalendarReturnType;
  classNames?: SlotsToClasses<CalendarSlots>;
  currentMonth: CalendarDate;
  firstDayOfWeek?: "sun" | "mon" | "tue" | "wed" | "thu" | "fri" | "sat";
}

export function CalendarCell(originalProps: CalendarCellProps) {
  const {state, slots, isPickerVisible, currentMonth, classNames, firstDayOfWeek, ...props} =
    originalProps;

  const ref = useRef<HTMLButtonElement>(null);

  const {
    cellProps,
    buttonProps,
    isPressed,
    isSelected,
    isDisabled,
    isFocused,
    isInvalid,
    formattedDate,
  } = useCalendarCell(
    {
      ...props,
      isDisabled: !isSameMonth(props.date, currentMonth) || isPickerVisible,
    },
    state,
    ref,
  );

Currently CalendarCell hardcodes isDisabled for dates outside the visible month:

This makes all dates from previous/next month non-interactive, even though React Aria’s useCalendarCell and RangeCalendar support handling arbitrary dates. This behavior is not configurable via props,

It should be possible to control this behavior via a prop, e.g.:

allowOutsideMonthSelection?: boolean

Suggested improvement

isDisabled:
(!allowOutsideMonthSelection && !isSameMonth(props.date, currentMonth)) ||
isPickerVisible