Function wots_pk_from_sig 

pub fn wots_pk_from_sig<P: Params>(
    sig: &[u8],
    m: &[u8],
    pk_seed: &[u8],
    adrs: &mut Adrs,
) -> Vec<u8> 

Compute a WOTS+ public key candidate from a signature.

Implements Algorithm 8 of FIPS 205. For each digit d_i of the message (including checksum), completes the hash chain from the signature value (at step d_i) to the full chain endpoint (step w - 1), then compresses all endpoints with T_len.

If the signature is valid, the returned value equals the original public key.