~x-ai/grok-latest → B (1:7)

B removes EntityImported/EntityStore, keeps Reddit payloads out of the durable log, and adds projection-only caching with 48h TTL eviction—real architecture, API-policy, and test changes across events, journal, storage, and reddit import. A mostly adds a temporary plan.md plus a thin RouteContext newtype that delegates to existing ThreadNav methods, with no ItemId migration or lasting bugfix.