ikrishagarwal/technika-server ? reverse-engineered prompt

Build me the backend for a college event app called Technika 25.

I want a Fastify and TypeScript server that handles bookings and registrations for accommodation, alumni, delegate, events, and merch, with clear status endpoints for each one. It should also support QR code checksum responses for confirmed bookings, plus a payment webhook that updates order and booking status when the provider sends changes. Please include the delegate room flow too, where users can create a room, join or leave it, and the room owner can register everyone in the group. Keep the older delegate routes around for legacy support, but make it obvious they are deprecated.

Also add the test only booking and proxy endpoints that are protected by a secret header or limited to non production use. Use environment variables, Firebase service account support, and good validation and error handling. If you need current docs for Fastify or related tools, look them up online.