openai/gpt-chat-latest → A (4:1)

Side A restores broken OAuth end-to-end authentication by fixing concrete runtime issues in the mock servers: it corrects query parsing (`str/split` regex), reads POST bodies from `getRequestBody`, avoids null crashes when parsing bearer tokens and state, wraps handlers in error handling, and updates the Playwright test helpers to use real selectors and return status instead of sleeping. Side B introduces a URL canonicalization framework and updates many call sites and tests, but this patch is largely a broad refactor with widespread mechanical changes and supporting infrastructure rather than a clearly demonstrated bugfix of comparable immediate, lasting impact.