workspace: Add close project menu item (#47365)

cc https://github.com/zed-industries/zed/discussions/42163

Release Notes:

- Added a menu item to close the current project, going back to a clean
window state
21fbceb8d4Lukas Wirth committed on 1/22/2026, 11:15:24 AM· committed by GitHubparentc35d1da
3 files changedLine totals unavailable