Variable lifetime of token

[otvegg]

What

• Add an auto-login endpoint so clients don’t need to log in with username/password every time.
• Allow variable token lifetimes, so clients can request short-lived or long-lived tokens depending on the use case.

Why

• Improve developer and user experience.
• Enable “remember me” functionality.

Acceptance Criteria

• Auto-login endpoint available.
• Token lifetimes configurable (predefined tiers).
• Documentation updated with usage examples.
• Test if correct tokens are retrieved