openai/gpt-chat-latest → B (4:3)

Side B removes the legacy GitDiscovery projection path and makes the evidence model authoritative by requiring evidence metadata on Emission, simplifying epoch/commit pages to rely only on Evidence envelopes and updating tests accordingly. Side A improves the vote-compare UI with a fullscreen layout, better edge-history sorting/display, and live preview updates after posting, but those are primarily user-interface enhancements rather than a core architectural simplification.