Function dh_public_key_from_scalar 

pub fn dh_public_key_from_scalar(scalar: [u8; 32]) -> DHPublicKey

Convert a scalar to a DH public key using the X25519 standard generator base point

libcrux_curve25519::secret_to_public uses the standard X25519 base point G = 9 (defined as [9, 0, 0, 0, …] in the HACL implementation, see g25519 in their code)