pub fn extended_rung(rec: &OrbitRecord, primes: &[u64]) -> ProofRungExpand description
The orbit’s ladder placement under the characteristic-extended cascade
(weakest_crushing_rung_with_char), recomputed from the representative cover. The audit-gap
closer: an orbit the router crushes via its mod-p specialist while the legacy ladder pays an
algebraic price (OrbitRecord::router_beats_ladder) lands on its ModCount { p } rung here;
every cover outside the mod-p population is placed exactly as the legacy ladder places it.