// SPDX-License-Identifier: AGPL-3.0-or-later
// Copyright (c) 2026 ReifyDB
//! Authentication method implementations. Each method is self-contained - it owns its credential format,
//! verification logic, and challenge state - and registers with the `registry/` so the service can pick the
//! right one for an incoming request. Adding a new method (a new IDP, a new key type) means writing one of these
//! modules and registering it; the rest of the auth surface is method-agnostic.