openai/gpt-chat-latest → A (3:1)

Side A includes functional project updates by changing the development task to run the renamed `sorter2-server`, updating the corresponding data environment variable (`SORTER2_DATA_DIR`), and ignoring the new `dev-data/` directory, which are lasting maintenance changes beyond UI tweaks. Side B is almost entirely a cosmetic adjustment to the new-thread interface (removing labels/header, changing button text to `+`/`-`, and deleting a toolbar), with little impact on project behavior.