gpui_linux: Add support for open_window in headless client (#60359)

This actually makes it possible for Linux headless client to have
working windows for computation (well, we are in headless mode after
all). This also matches macOS headless client behaviour.

Release Notes:

- N/A
f4364d870eJakub Konka committed on 7/3/2026, 3:20:09 PM· committed by GitHubparentaabcd71
3 files changedLine totals unavailable