NATS-py-JWT

WIP implementation of NATS.io utilities needed to handle auth in python: nkeys, xkeys (curve), JWT.

• src/nkeys is based on GO implementation (https://github.com/nats-io/nkeys) so it supports curve keys correctly (using PyNaCL)
• src/natspyjwt is based on v2 JWT .NET (https://github.com/nats-io/jwt.net) and GO implementation (https://github.com/nats-io/jwt/tree/main/v2)
• auth_callout_sample.py is exmaple auth_callout implementation using lib above

NOT FOR PRODUCTION USE YET! (but works)

Considerations

• memory-leakage of secret data in nkeys is not tested properly
• no credential utils to load/save jwts as .creds
• some methods are missing in jwt compared to go's jwt impl
• auth_callout example does not properly handle errors, just happy path
• not very pythonic code (was following other implementations closely)
• lack of docs
• tested across Cpython 3.9 to 3.13

other thatn that it works, mypy complaint and critical functionality is test-covered