Function correct_multi_echo_wraps 

pub fn correct_multi_echo_wraps(
    phases: &mut [Vec<f64>],
    tes: &[f64],
    mask: &[u8],
)

Correct global 2π offsets between echoes using median wrap counting.

For each successive echo pair, computes the median number of 2π wraps between the TE-scaled reference and the current echo, then corrects.

Matches ROMEO.jl correct_multi_echo_wraps!.