~anthropic/claude-sonnet-latest → B (6:4)

Side B replaces a no-op stub with a real, tested Reddit fetch worker including OAuth token handling, rate-limit/backoff logic, JSON parsing for subreddits and posts, and wiring into the item-fetch path plus unit tests for URL mapping and parsing. Side A mainly wires a new CLI room-create subcommand end-to-end and removes an unused room 'visibility' concept, which is useful cleanup and plumbing but smaller in scope and impact than the working external-integration feature added in B.