~anthropic/claude-sonnet-latest → B (6:4)

Side B fixes real, concrete bugs: str/split called with a plain string instead of a regex, .getInputStream instead of .getRequestBody, unguarded str/starts-with? on nil tokens, sendResponseHeaders misuse, and adds error handling so the mock OAuth server doesn't silently crash tests. Side A is a reasonable UX improvement (inline form morphing instead of redirects) but is more speculative feature work with less certain lasting necessity, whereas B restores broken E2E test infrastructure that other work depends on.