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

Side A makes several coordinated, verifiable fixes (correct out-of-band delegate passing, error-instead-of-silent-fallback for small sibling pools, dead button removal, route rename) with updates propagated consistently across server code, tests, and browser test scripts. Side B is a minimal one-line fix defining a missing env var to resolve a NameError, which is valid but much narrower in scope and impact than Side A's multi-part correctness and UX improvements.