~x-ai/grok-latest → A (3:1)

A introduces lasting architectural value by offloading bulky Reddit entity JSON from the in-memory GlobalTree into a RocksDB-backed EntityStore (via the vendored durable crate) and by replacing full event-log materialization with true streaming replay, which directly cuts startup RAM; the integration touches entity_store, event_log, reducer, state and reddit paths with accompanying tests. B is a correct, necessary production bugfix (force OAuth when credentials exist, refresh on 401/403, avoid the public www.reddit.com block page, plus a fly.toml pin) but is narrower in scope and impact.