This handbook is mandatory. Every exported function/class and every HTTP
endpoint must have a section. CI (bun run handbook:check / node scripts/check-handbook.mjs)
fails the PR otherwise.
- Functions:
## Function: name - Endpoints:
## Endpoint: METHOD /path
This repo has no UI screens. UI screens live in 21gifts/app and 21gifts/website.
A PR that adds an export or route without a handbook section is rejected.