Module auth 

Authentication module for the HTTP API

Provides:

• User credential management (loaded from JSON file)
• Password verification using PBKDF2-HMAC-SHA256
• Bearer token generation and validation using HMAC-SHA256

Structs

AuthService

Authentication service that manages credentials and tokens

TokenRequest

Request body for token generation

TokenResponse

Response body for successful token generation

UserCredential

A user credential stored in the credentials file