cdc660c15f
Address review feedback on PR #101: 1. Capture resp.StatusCode and Retry-After header *before* passing resp to handleResponse, making ownership transfer explicit. Previously the caller read resp.StatusCode after handleResponse had closed the body — correct but fragile coupling. 2. Add panic guard ensuring backoff slice length equals maxAttempts-1. Previously the relationship was implicit and could silently break if maxAttempts were changed without updating the default backoff.