Protect selected windows from screen capture

Add capture privacy rules for windows, transient children, overview previews and client cursors, with separate capture rendering and deferred-frame invalidation. Keep detached close snapshots out of captures after clients leave the registry.

Validated with release workspace tests, private compositor/EGL regressions, and an isolated release PipeWire capture test.

compositor/src/overview.rs

@@ -1046,7 +1046,6 @@ impl OverviewMotion {
 
     #[cfg(test)]
     pub(crate) fn presented_rect(&self, id: WindowId, normal: Rect) -> Rect {
-
         self.presentations.get(&id).map_or(normal, |p| p.current)
     }