Commit da5484b61 disabled the Window Controls Overlay on all Linux
(non-Windows, non-WSL) with the note that WCO is a Windows/macOS-only
Electron feature. However, several Linux compositors (KDE/KWin,
GNOME/Mutter) do support it — plain Electron titleBarOverlay paints
native min/max/close buttons that were working before that change.
Narrow the exclusion to only WSLg, where the RDP host draws its own
window controls and an Electron overlay would leave a dead gap.
Fixes: da5484b61 ("fix(desktop): WSL2 clipboard image paste + Linux titlebar overlay")