Use transparent clear color for opaque windows on Linux (#46281)

https://github.com/zed-industries/zed/pull/45423 changed the Blade
renderer to use a white clear color for "opaque" windows. This interacts
poorly with our client-side decorations, causing the shadows around the
window to be drawn over a white background.

Release Notes:

- N/A
a3733b8f60John Tur committed on 1/7/2026, 7:39:57 PM· committed by GitHubparent19e7ee5
1 file changedLine totals unavailable