~x-ai/grok-latest → B (2:1)

B replaces an O(n²) candidate-sort that re-derived rank-centrality keys per pair with linear attach/bridge growth plus a single zip pass after one RC order, which is a lasting core-algorithm and scalability fix. A correctly drops the Tokio read guard before layout so writers are not blocked, but that is a localized locking hygiene fix on one handler versus B’s broader complexity and performance win.