collab: Add screen selector (#31506)

Instead of selecting a screen to share arbitrarily, we'll now allow user
to select the screen to share. Note that sharing multiple screens at the
time is still not supported (though prolly not too far-fetched).

Related to #4666

![image](https://github.com/user-attachments/assets/1afb664f-3cdb-4e0a-bb29-9d7093d87fa5)

Release Notes:

- Added screen selector dropdown to screen share button

---------

Co-authored-by: Kirill Bulatov <kirill@zed.dev>
Co-authored-by: Cole Miller <cole@zed.dev>

crates/gpui/src/platform/linux/headless/client.rs

@@ -73,7 +73,7 @@ impl LinuxClient for HeadlessClient {
     #[cfg(feature = "screen-capture")]
     fn screen_capture_sources(
         &self,
-    ) -> futures::channel::oneshot::Receiver<anyhow::Result<Vec<Box<dyn crate::ScreenCaptureSource>>>>
+    ) -> futures::channel::oneshot::Receiver<anyhow::Result<Vec<Rc<dyn crate::ScreenCaptureSource>>>>
     {
         let (mut tx, rx) = futures::channel::oneshot::channel();
         tx.send(Err(anyhow::anyhow!(

crates/gpui/src/platform/linux/platform.rs

@@ -56,7 +56,7 @@ pub trait LinuxClient {
     #[cfg(feature = "screen-capture")]
     fn screen_capture_sources(
         &self,
-    ) -> oneshot::Receiver<Result<Vec<Box<dyn crate::ScreenCaptureSource>>>>;
+    ) -> oneshot::Receiver<Result<Vec<Rc<dyn crate::ScreenCaptureSource>>>>;
 
     fn open_window(
         &self,
@@ -245,7 +245,7 @@ impl<P: LinuxClient + 'static> Platform for P {
     #[cfg(feature = "screen-capture")]
     fn screen_capture_sources(
         &self,
-    ) -> oneshot::Receiver<Result<Vec<Box<dyn crate::ScreenCaptureSource>>>> {
+    ) -> oneshot::Receiver<Result<Vec<Rc<dyn crate::ScreenCaptureSource>>>> {
         self.screen_capture_sources()
     }
 

crates/gpui/src/platform/linux/wayland/client.rs

@@ -672,7 +672,7 @@ impl LinuxClient for WaylandClient {
     #[cfg(feature = "screen-capture")]
     fn screen_capture_sources(
         &self,
-    ) -> futures::channel::oneshot::Receiver<anyhow::Result<Vec<Box<dyn crate::ScreenCaptureSource>>>>
+    ) -> futures::channel::oneshot::Receiver<anyhow::Result<Vec<Rc<dyn crate::ScreenCaptureSource>>>>
     {
         // TODO: Get screen capture working on wayland. Be sure to try window resizing as that may
         // be tricky.

crates/gpui/src/platform/linux/x11/client.rs

@@ -1448,7 +1448,7 @@ impl LinuxClient for X11Client {
     #[cfg(feature = "screen-capture")]
     fn screen_capture_sources(
         &self,
-    ) -> futures::channel::oneshot::Receiver<anyhow::Result<Vec<Box<dyn crate::ScreenCaptureSource>>>>
+    ) -> futures::channel::oneshot::Receiver<anyhow::Result<Vec<Rc<dyn crate::ScreenCaptureSource>>>>
     {
         crate::platform::scap_screen_capture::scap_screen_sources(
             &self.0.borrow().common.foreground_executor,