openai/gpt-chat-latest → A (9:1)

Side A performs a substantive architectural refactor by extracting major forum responsibilities into new modules (such as access, ingest, navigation, room members, and new-thread handling), introduces reusable helpers like ThreadNav and permission checks, and adds a useful profiling script for sampling fixture processes. Side B is overwhelmingly workspace-wide formatting plus tooling updates (pinning rustfmt/clippy, VS Code settings, minor CSS cleanup), with little functional impact beyond developer ergonomics.