Function van_commitment_hash 

pub fn van_commitment_hash(
    g_d_new_x: Base,
    pk_d_new_x: Base,
    num_ballots: Base,
    vote_round_id: Base,
    van_comm_rand: Base,
) -> Base

Out-of-circuit governance commitment hash used by the builder and tests.

Delegates to van_integrity::van_integrity_hash with MAX_PROPOSAL_AUTHORITY as the proposal authority (fresh delegation). The value parameter is num_ballots (ballot count after floor-division), NOT the raw zatoshi sum.

This is public so client crates can compute the same VAN commitment that the delegation circuit constrains, while keeping byte parsing and amount policy in their own API layer.