Function make_hint_vec 

pub fn make_hint_vec(
    z: &[[i32; 256]],
    r: &[[i32; 256]],
    gamma2: i32,
    len: usize,
) -> ([[i32; 256]; 8], usize)

Apply make_hint to every coefficient of two polynomial vectors.

Returns (h, count) where h is the fixed array of hint polynomials and count is the total number of 1-bits across all polynomials. The count is compared against omega to decide whether to accept the signature.