Sorting each batch is not a global order

// before: every ready node installs this round; priority only reorders inside the round
let round = ready(worklist);
round.sort(byPriorityDesc);

// after: only the highest-priority ready nodes go this round; others wait
const top = Math.max(...round.map(n => n.priority));
round = round.filter(n => n.priority === top).sort(byId);