Make GitRepository::status async and remove cx parameter (#27514)

This lays the groundwork for using `status` as part of the new agent
panel.

Release Notes:

- N/A

crates/remote_server/src/unix.rs

@@ -445,7 +445,7 @@ pub fn execute_run(
         let extension_host_proxy = ExtensionHostProxy::global(cx);
 
         let project = cx.new(|cx| {
-            let fs = Arc::new(RealFs::new(None));
+            let fs = Arc::new(RealFs::new(None, cx.background_executor().clone()));
             let node_settings_rx = initialize_settings(session.clone(), fs.clone(), cx);
 
             let proxy_url = read_proxy_settings(cx);