Old code assumed result_data was a JSON string and ran JSON.parse on it,
falling back to returning the value verbatim on parse error. When the
backend ships result_data as a dict (e.g. compose tasks return
{music_task_id, tracks}), JSON.parse threw, the catch returned the raw
object, and React threw error #31 'Objects are not valid as a React
child' the moment the user expanded the task row.
Extract formatResultData helper: object → JSON.stringify, JSON string
→ parse then pretty-print, plain string → as-is.
Regression tests cover all three input shapes.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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