openai/gpt-5.2-chat → B (3:2)

Side B fixes a concrete runtime error by defining `GITHUB_API_BASE_URL` with a default and `.rstrip("/")`, resolving a NameError in the GitHub OAuth callback path. Side A improves test maintainability by replacing hand-enumerated suites with a single auto-discovered `:all` suite, but it’s a configuration refactor rather than a direct functional bugfix impacting production behavior.