~x-ai/grok-latest → B (2:1)

B removes an entire dual-path legacy projection layer (_legacy_commit_row/_legacy_observation and GitDiscovery/Emission fallbacks on epoch/commit pages), making Evidence envelopes the sole source of truth and tightening Emission required fields—durable architectural cleanup. A’s real wins are the out-of-band delegate attribution fix and stopping the bad all-items fallback, but they sit beside lower-impact renames and UI chrome removal, so less structural lasting value.