Function homotopy_group_size 

pub fn homotopy_group_size(modulus: usize, n: usize, k: usize) -> usize

Extract the homotopy group π_k of K(A, n) directly from the Kan complex, by horn-filling. This is the homotopy hypothesis realized computationally — given the ∞-groupoid object, read its homotopy back out. Returns |π_k|: |A| at k = n, trivial (1) everywhere else. (K(A, n≥2) is 1-connected, so π_0 = π_1 = 1 by construction.)