JWT specifications

Having a detailed specification for JWT token generation and the usage in the different APIs (this is partially documented already via the claims sections). This is primarily for the Wings API but also includes a couple of endpoints from the client API.

Start by reviewing the existing claims sections and the documented Wings API and client API endpoints. Done means providing a detailed specification of JWT token generation and how JWTs are used across the identified APIs.

索引モデルが issue の本文から書いたものです。