Changelog

v0.2.1 (2026-05-23)

Add MetamorphicCrypto.Hybrid.security_level/0 type (:cat3 | :cat5)
MetamorphicCrypto.Hybrid.generate_keypair/1 now accepts an optional security level — generate_keypair(:cat5) for ML-KEM-1024, generate_keypair() for ML-KEM-768 (default, unchanged behavior)
MetamorphicCrypto.Hybrid.seal/3 and seal_raw/3 now accept an optional security level parameter
MetamorphicCrypto.Seal.seal_for_user/3 and seal_for_user_raw/3 now accept a :level option (:cat3 or :cat5) for choosing the PQ security level when a PQ public key is provided
Existing generate_keypair_1024/0, seal_1024/2, and seal_raw_1024/2 are preserved as convenience aliases
All changes are backwards compatible — no NIF or binary changes required

Switch from vendored metamorphic-crypto Rust source to metamorphic-crypto v0.2.0 on crates.io (no user-facing changes — the public Elixir API is fully backwards compatible)
Add ML-KEM-1024 + X25519 (Cat-5, NIST Category 5, ~AES-256) hybrid encryption:
- MetamorphicCrypto.Hybrid.generate_keypair_1024/0 — generate Cat-5 keypair
- MetamorphicCrypto.Hybrid.seal_1024/2 — encrypt with Cat-5
- MetamorphicCrypto.Hybrid.seal_raw_1024/2 — encrypt raw bytes with Cat-5
MetamorphicCrypto.Hybrid.open/2 now auto-detects Cat-3 (v2) and Cat-5 (v3) ciphertext
MetamorphicCrypto.Hybrid.hybrid_ciphertext?/1 now detects both v2 and v3 formats

Add explicit targets list to RustlerPrecompiled config
- Prevents download attempts for unsupported platforms (e.g. arm-unknown-linux-gnueabihf)
- mix rustler_precompiled.download --all now only fetches the 5 supported targets

Fix precompiled NIF loading on macOS and Windows
- Binary inside tar archive was named incorrectly (libmetamorphic_crypto_nif.dylib instead of the versioned .so name that RustlerPrecompiled expects)
- Users without Rust installed would get nif_not_loaded errors