Supervisor 调用 exit 结束时，若助手正文只有「交付终审报告：」这类开场白，而真正内容写在 final_result 里，最终回复会漏掉报告。本次修复会优先采用 exit.final_result，并与开场白合并展示，避免只看到空壳文案。

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When Supervisor ends via exit with only a short intro in the assistant text and the real report in final_result, the final reply used to drop that report. This fix prefers exit.final_result and merges it with the intro so the full audit report is shown.