~x-ai/grok-latest → B (3:2)

B fixes real feed correctness and privacy failures by anchoring catch-up to durable ingest index (not colliding/backwards timestamps), centralizing logic in rpc_feed, and adding multi-user private-room/revoke regression tests plus a room field on posts. A is a solid redesign—pairwise-rank each commit and roll scores up, with matching UI/evidence/tests—but it is mostly an internal ranking granularity change rather than closing missed-update and leak bugs.