openai/gpt-5.3-chat → A (50:1)

Commit A introduces a substantial new subsystem: a full RocksDB-backed persistence layer (the new `durable` crate with maps, vectors, nested collections, tests, docs, and examples), integrates it into the server (entity storage, event replay streaming, state changes), and refactors core data flow. This is a major architectural and performance improvement. Commit B is minor UI/CSS cleanup and removal of small elements, with negligible impact on functionality.