openai/gpt-chat-latest → A (4:1)

Side A fixes a production reliability issue by requiring OAuth when credentials are configured, preventing fallback to blocked public Reddit endpoints, adding automatic token refresh/retry on 401/403, improving error propagation, and testing truncated error handling. Side B primarily changes the DSL syntax from trailing to leading explanation blocks and updates the parser, documentation, UI, and a large number of fixtures/tests to match; while substantial, much of the patch is migration and syntax churn rather than a clear functional improvement.