openai/gpt-chat-latest → B (4:1)

Side B introduces reusable URL infrastructure by centralizing room route encoding/decoding (`room_route_segment`/`room_id_from_route_segment`), updating routing and link generation across the application, and adding URL normalization utilities (including canonicalization for YouTube and query ordering) with focused tests. Side A mainly replaces a complex autocomplete/navigation system with a much simpler paste-and-go flow by deleting the parser graph and related UI, which simplifies maintenance but also removes functionality rather than adding broadly reusable project capabilities.