openai/gpt-chat-latest → A (4:1)

Side A implements substantial infrastructure changes: it introduces a RocksDB-backed `durable` workspace crate, moves raw Reddit entity JSON out of the in-memory tree into a persistent `EntityStore`, and replaces whole-file event loading with streaming replay to reduce startup memory while updating reducers and tests accordingly. Side B is a solid correctness improvement—changing feed catch-up to use durable ingest order instead of timestamps, enforcing room visibility during feed generation, and adding regression tests—but it is a targeted behavioral fix rather than the broad persistence and scalability architecture added in Side A.