openai/gpt-chat-latest → B (9:1)

Side B introduces a substantial architectural change: it replaces many specialized REST endpoints with a unified RPC API, updates the CLI to use batched RPC commands, refactors the reducer and event model from thread-centric to room/scope-aware data structures, and propagates those changes through tests and types. Side A mainly removes the obsolete monolithic `forum.rs` in favor of the already-split `forum/` module tree and adds `forum/mod.rs`, which is a useful cleanup to resolve module ambiguity but is primarily structural rather than adding new project capabilities.