openai/gpt-chat-latest → A (4:3)

Side A delivers new behavior: it introduces a composable URL canonicalization/rules engine (`server/src/url_rules`), makes full `https://` URLs the canonical identity, centralizes parsing/parent/breadcrumb logic, updates projection/event handling to canonicalize IDs at apply time, and adds tests for Reddit/YouTube normalization and breadcrumb behavior. Side B is a broad architectural refactor replacing `CanonicalItemUrl` with `ItemId` across the codebase and moving wire helpers into new modules, but most changes are type migration and call-site updates rather than adding new user-visible functionality or fixing concrete bugs.