Exposes user ListenBrainz config (token_set bool, enabled, last_scrobbled_at)
via write-only token semantics; enforces no-enable-without-token at the API layer.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Resolves /api/* callers from session cookie first, Authorization
bearer second. Touches last_seen on success for future active-
sessions UI. Adds GetUserByID query used by the middleware.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>