openai/gpt-chat-latest → A (3:2)

Side A adds a substantial new URL canonicalization subsystem: a semantic graph/DFA with declarative graph builder, URL parsing and normalization, generic fallback behavior, breadcrumb generation, encoding/security handling, and extensive unit and integration tests for Reddit, YouTube, and generic URLs. Side B is a large architectural refactor that consolidates many REST endpoints into an RPC layer and renames thread concepts to rooms while preserving existing behavior, but much of the patch is migration and code movement rather than introducing comparable new end-user functionality.