openai/gpt-chat-latest → A (4:3)

Side A resolves a structural module-root ambiguity by deleting the leftover monolithic `server/src/html/forum.rs`, introducing `forum/mod.rs`, and making the split `forum/` modules the single authoritative implementation. This is a lasting architectural cleanup that prevents duplicate module resolution and maintenance drift, whereas Side B adds a useful but narrower feature: a `CopyGardenRank` UI action, clipboard markdown generation, button integration, and tests for copying garden rankings.