openai/gpt-chat-latest → A (9:2)

Side A performs a substantial architectural refactor by introducing a structural `ItemId` type, extracting wire-normalization into `item_wire`, and propagating the new identity model throughout reducers, ranking, routing, APIs, HTML, and tests while replacing `CanonicalItemUrl`. These changes centralize item identity and routing logic (for example `RouteContext::item_href` and `ThreadNav::garden_item_href`) and reduce string-based handling. Side B adds useful deployment artifacts (Dockerfile, Fly config) and standalone persistence utilities (`EventLog`, `ViewStore`), but they are largely additive infrastructure and are not integrated into the project's core behavior in this patch.