Headless month-grid + drag/shift range-select hook. Returns the 42-cell grid, today/cursor state, range state, and mouse handlers. Domain-agnostic -- pair with EventCalendar or any month-shaped UI by reading the returned values. Also exports isoDate / dateFromKey / dayDiff helpers.
npx shadcn@latest add https://uipkge.dev/r/react/use-month-grid.jsonuse-month-grid