openai/gpt-5.2-chat → A (50:1)

Commit A introduces a substantial architectural change: adds a full RocksDB-backed `durable` workspace crate (with maps, vectors, nesting, tests, docs, examples), integrates it into the server, offloads entity payloads to disk, and rewrites event log replay to stream line-by-line for reduced RAM usage. This spans many new modules and core state changes. Commit B contains only minor UI/CSS tweaks and small HTML removals. The scope, complexity, and impact of A vastly exceed B.