fix(desktop): honor vibrancy toggle for window transparency

Tie macOS window transparency to the vibrancy setting so disabling vibrancy actually removes transparent backgrounds. Clarify settings copy that full transparency changes take effect for new windows or after restart.

packages/desktop/src-tauri/src/main.rs

@@ -2573,7 +2573,7 @@ fn apply_platform_window_config<M: Manager<tauri::Wry>>(
 ) -> WebviewWindowBuilder<'_, tauri::Wry, M> {
     #[cfg(target_os = "macos")]
     let builder = builder
-        .transparent(true)
+        .transparent(read_desktop_vibrancy_enabled())
         .hidden_title(true)
         .title_bar_style(tauri::TitleBarStyle::Overlay)
         .traffic_light_position(tauri::Position::Logical(tauri::LogicalPosition {