nbf immediately valid

• Fixed JWT token "not before" (nbf) claim timing. Tokens are now immediately valid upon issuance (nbf = iat)

Improve error management

• Updated dependencies in package.json:
  • @dwtechs/checkard to 3.5.1
  • @dwtechs/hashitaka to 0.3.1
• Improved error messages using Hashitaka and Checkard errors

Initial version

• Initial version