openai/gpt-chat-latest → A (5:2)

Side A introduces a durable architectural separation by extracting identity parsing (`identity.rs`) and path normalization (`canonical_path.rs`), removing implicit identity rewriting from the reducer, changing delegates to `Option<String>`, and enforcing strict stored-form identities across APIs while keeping HTML-specific `@` rendering. Side B fixes a real multi-user bug by eliminating shared browser sentinel delegates and adding strong regression tests, but it is a focused follow-up built on the broader identity model established in Side A.