audio_generate answers an AudioGenerationResponse, a pydantic model, and
_generate_music read it with .get(). Every compose asking for AI music raised
"'AudioGenerationResponse' object has no attribute 'get'", warned "rendered
without music", and then SUCCEEDED -- silent. That is why it lasted: the render
never failed, so only someone watching the finished video would notice, and
"AI composed" music has been off in production the whole time.

Both shapes are accepted, since the same call is reachable through paths that
answer a plain dict, and a non-dict item is coerced rather than assumed.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014T3rZnLhydX9QqUcfBbqLu