uselesskey-axum

Drop-in auth-test helpers for axum, built on deterministic uselesskey fixtures.

This crate intentionally focuses on test ergonomics:

• jwks_router() for a deterministic JWKS endpoint
• oidc_router() for OIDC discovery metadata
• mock_jwt_verifier_layer() for bearer auth checks in tests
• TestAuthContext extractor + injection helpers

It is not a production auth middleware package.