project_panel: Add file comparison function, supports selecting files for comparison (#35255)

Closes https://github.com/zed-industries/zed/discussions/35010
Closes https://github.com/zed-industries/zed/issues/17100
Closes https://github.com/zed-industries/zed/issues/4523

Release Notes:

- Added file comparison function in project panel

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Co-authored-by: Kirill Bulatov <kirill@zed.dev>
e8db429d24mcwindy committed on 8/7/2025, 6:34:12 PM· committed by GitHubparent53b69d2
8 files changedLine totals unavailable