agent_panel: Make thread title editing more discoverable (#56485)

This PR adds an edit icon button in the thread title to better
promote/communicate that that's an editable label.


https://github.com/user-attachments/assets/efd69efc-ad9b-4c48-9640-e21b09d70226

Release Notes:

- N/A
21277b3b98Danilo Leal committed on 5/12/2026, 4:25:47 AM· committed by GitHubparent1a2e50e
1 file changedLine totals unavailable