openai/gpt-5.3-chat → A (9:1)

Side A introduces a full invite system end-to-end (RPC minting, auth redemption flow, state management, reducer updates, CLI commands, and integration tests), plus expands thread modeling with system items, while Side B only makes an existing pin icon clickable and adjusts CSS/tests. The former adds new core capabilities and data flows; the latter is a localized UI improvement.