By: Tom Sydney Kerckhove <syd@cs-syd.eu>
Mutation: show a coloured [X/Y] progress counter while testing mutations Prefix each per-mutation progress line with a cyan [X/Y] counter. X is the mutation's stable 1-based position in the manifest (a pure, precomputed Map MutationId Int looked up per mutation, not a shared mutable counter), so the numbers are deterministic rather than dependent on concurrent start order; Y is the total mutation count.