Function ed25519_to_x25519_public 

pub fn ed25519_to_x25519_public(
    ed25519_private_key: &SigningKey,
) -> Result<PublicKey, CryptoError>

Convert Ed25519 public key to X25519 public key Derives X25519 public key from the corresponding Ed25519 private key Note: This is a simplified approach that requires the private key