DateRangeCalendar: expose resetOnSelect so range consumers can restart a range on click

[retrofox]

Problem

In DateRangeCalendar, clicking a day while a complete range is selected never restarts the range: react-day-picker's default addToRange moves the endpoint nearest to the clicked day instead. A user's natural "click start, click end" gesture can even cancel out exactly and leave the original range untouched. react-day-picker supports resetOnSelect for exactly this, and it already reaches DayPicker through the ...props spread, but it isn't part of DateRangeCalendarProps, so typed consumers can't opt in without a cast against an undocumented pass-through.

Proposed Solution

Expose resetOnSelect as a first-class prop on the range calendar, and document that in controlled mode the first click emits a half-open range ({ from, to: undefined }) the consumer must render back for the two-click flow to work.

Tasks

• Add resetOnSelect to the range props in packages/ui/src/calendar/types.ts and forward it explicitly
• Document the controlled half-open emission in the README
• Add a story covering restart-on-click selection
• Consider mirroring the prop in core's copy (@wordpress/components private DateRangeCalendar)

Location

• packages/ui/src/calendar/date-range-calendar/index.tsx
• packages/ui/src/calendar/types.ts

Context: found while fixing the date range picker in Automattic/jetpack#50179, which currently implements the restart-on-click behavior consumer-side.