## What changed
- Hide the working-status indicator when finalized assistant output is committed to the transcript, including single-line final answers.
- Restore the indicator when image generation begins during a running task after its streamed preamble has been flushed.
## Testing
- Add snapshot coverage for a single-line final answer and for image generation following a single-line preamble.
GitOrigin-RevId: e294a11cda3f0ce46f2bbed1be2a1380c9c73085