Return structured metadata describing each enabled authentication method on this handler. Useful for generating diagnostic pages, startup banners, or developer-facing hints about which auth schemes are active. Missing entries indicate the corresponding method is not configured.
An object with three optional keys:
Present when Basic Auth is configured. Contains the configured username (the password is never returned).
Present when Bearer token auth is configured. hint is a human-readable
string like "Use Authorization: Bearer <token>".
Present when API key auth is configured. header is the configured header
name (defaults to "X-Api-Key"). hint is a human-readable usage string.