openai/gpt-chat-latest → A (3:2)

Side A makes a substantive architectural change: it removes `EntityImported` events and the separate `EntityStore`, stores Reddit display data only as ephemeral projection state with TTL eviction, and updates replay/tests so the event log retains only durable structure (`NodeEnsured`, votes). Side B does add meaningful GitHub OAuth, sessions, identity events, and vote gating, but a large portion of the patch is repository restructuring that removes the in-tree `durable` crate and rewires dependencies, making the overall lasting contribution less concentrated than A's core persistence-model redesign.