~anthropic/claude-sonnet-latest → B (85:15)

Side B is a substantial architectural change: it replaces a sprawling set of ad-hoc REST endpoints with a unified RPC batch protocol, reworks the reducer's room/thread model (ScopeId, RoomState vs ForumThreadState), updates the CLI to use scoped subcommands and RPC calls, and updates the full test suite and integration scripts to match — a real, cohesive advance in the project's data model and API surface. Side A is a much smaller, purely mechanical fix (deleting a duplicate leftover forum.rs so `mod forum` resolves), which is necessary but minor cleanup rather than new capability or design.