Windows screen sharing (#34223)

Release Notes:

- N/A

---------

Co-authored-by: localcc <work@localcc.cc>
Co-authored-by: Peter Tripp <petertripp@gmail.com>

crates/gpui/src/platform/windows/platform.rs

@@ -434,16 +434,14 @@ impl Platform for WindowsPlatform {
 
     #[cfg(feature = "screen-capture")]
     fn is_screen_capture_supported(&self) -> bool {
-        false
+        true
     }
 
     #[cfg(feature = "screen-capture")]
     fn screen_capture_sources(
         &self,
     ) -> oneshot::Receiver<Result<Vec<Box<dyn ScreenCaptureSource>>>> {
-        let (mut tx, rx) = oneshot::channel();
-        tx.send(Err(anyhow!("screen capture not implemented"))).ok();
-        rx
+        crate::platform::scap_screen_capture::scap_screen_sources(&self.foreground_executor)
     }
 
     fn active_window(&self) -> Option<AnyWindowHandle> {