Verify a Groth16 proof (BLS12-381). vk_bytes: alpha(G1) || beta(G2) || gamma(G2) || delta(G2) || ic proof_bytes: a(G1) || b(G2) || c(G1) pub_signals_bytes: concat of big-endian Fr (32 bytes each), length = n_pub.
fn verify(
env: soroban_sdk::Env,
vk_bytes: soroban_sdk::Bytes,
proof_bytes: soroban_sdk::Bytes,
pub_signals_bytes: soroban_sdk::Bytes,
) -> Result