Adds ML-DSA-44, ML-DSA-65, and ML-DSA-87 post-quantum signature algorithms to the ruby-jwt ecosystem, with optional hybrid EdDSA + ML-DSA mode. Uses liboqs via FFI.

Ruby C extension wrapping the ML-DSA post-quantum digital signature algorithm (NIST FIPS 204, formerly CRYSTALS-Dilithium). Bundles the PQClean clean C implementation for all three parameter sets: ML-DSA-44 (NIST Level 2), ML-DSA-65 (Level 3), and ML-DSA-87 (Level 5). Supports both hedged (random...