Function boolean_topology_hash 

pub fn boolean_topology_hash(a: &[Tri], b: &[Tri], op: BoolOp) -> u64

Topology fingerprint of a boolean result: each oriented Vid triangle rotated min-first (canonical start vertex, winding preserved), the list sorted, FNV-1a-hashed. Platform-stable — Vids are deterministic symbolic identities and the ray-cast classification is FMA-free f64.