Update frontend types, stores, and components to support name history display and new API fields.
- Add previousFirstName/previousLastName to User type and BookingUser type
- Add referral discount_source type and refunds array to Booking type
- Create nameDisplay.ts utility for rendering '(formerly ...)' labels
- Create booking.ts utility for booking-related helpers
- Update 25+ admin, payments, today, and account components to display
former names on booking cards, modals, appointment views, and user lists
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>