sum_tree: Replace rayon with futures (#41586)

Release Notes:

- N/A *or* Added/Fixed/Improved ...

Co-authored by: Kate <kate@zed.dev>
f2ce06c7b0Lukas Wirth committed on 10/31/2025, 10:39:01 AM· committed by GitHubparent7c29c6d
64 files changedLine totals unavailable