uselesskey-core-jwk-builder

SRP microcrate for JWKS composition used by uselesskey key fixtures.

• Stable, deterministic ordering by kid for JWKS entries.
• Deterministic tie-breakers for duplicate kid values based on insertion order.
• Zero secret material leakage in Debug output (delegated to JWK models).

The crate is consumed by:

• uselesskey-jwk for re-exported JwksBuilder
• uselesskey-core-jwk consumers that only need JWK model types