~anthropic/claude-sonnet-latest → A (9:1)

Side A makes substantive functional fixes: correct out-of-band delegate attribution, real bugfix replacing a silent fallback with an explicit error when the sibling pool is too small, removal of a broken/pointless UI feature, and a route rename applied consistently across code and tests. Side B merely deletes a scratch notes file, which is trivial housekeeping with no functional impact on the project.