openai/gpt-chat-latest → A (3:2)

Side A makes a substantive architectural cleanup by removing legacy GitDiscovery projection paths and requiring evidence-backed metadata, simplifying epoch/commit views to rely only on Evidence events and updating tests to enforce the new model. Side B improves the authentication UX by replacing redirects with inline HTML fragments and extending the shared JS form handler, but its impact is more localized to the web interface than A's system-wide data model and maintenance simplification.