Calendar range picker

A stateful two-month range calendar for booking a span of days, with clear and reserve actions. Do: Keep the Clear action available whenever a range is selected, separate from Reserve. Don't: Force a user to re-click through the whole range to correct a mis-click — that's what Clear is for. Do: Disable Reserve until both a start and end date are selected. Don't: Let a half-made range (just a start date) submit as if it were a valid booking. Use calendar-page when the user is picking a single day to view, not a multi-day span to reserve. Use checkout when the range is just one field within a larger purchase flow, not the whole card.