agent_ui: Improve thread import UX (#57791)

<img width="439" height="292" alt="image"
src="https://github.com/user-attachments/assets/90a39458-1ec5-4c73-922e-21cab8aa5a51"
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Release Notes:

- agent: Improved UX of agent import flow

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Co-authored-by: Danilo Leal <daniloleal09@gmail.com>
5a318bad74Bennet Bo Fenner committed on 6/5/2026, 7:18:05 AM· committed by GitHubparenteac0687
1 file changedLine totals unavailable