openai/gpt-5.3-chat → A (2:1)

Side A makes concrete improvements to the codebase: fixing clippy warnings, tightening patterns, simplifying code, adding a missing test annotation, and improving minor APIs and tests across multiple modules. These changes improve correctness, maintainability, and build hygiene. Side B is extensive but consists only of notes and a design document, which don’t affect the running system. While useful for planning, it doesn’t contribute executable value yet.