Secp256r1 Precompile (P256)

A native Solana program for verifying ECDSA signatures on the secp256r1 (P-256/prime256v1) elliptic curve, enabling WebAuthn and passkey-based authentication directly on-chain. P-256 is the curve used by Apple Face ID/Touch ID, Android biometrics, and FIDO2 security keys. This precompile allows Solana dApps to authenticate users via device biometrics without managing traditional private keys, significantly improving wallet UX.