openai/gpt-chat-latest → A (3:2)

Side A consolidates canonicalization, URL generation, and path newtypes into a shared `slug_types::paths` module, replaces ad hoc string helpers with strongly typed `GardenItemUrl`, `ForumThreadUrl`, and `TildeOntologyPath`, and updates API types to use those abstractions across the codebase. Side B fixes a real correctness bug by moving the zero-ratio guard before `ensure_item` and `voted_pairs.insert`, preventing ghost items and false voted pairs, but its impact is narrower than the architectural cleanup and type-safety improvements introduced by Side A.