Add user-visible output for remote operations (#25849)

This PR adds toasts for reporting success and errors from remote git
operations. This PR also adds a focus handle to notifications, in
anticipation of making them keyboard accessible.

Release Notes:

- N/A

---------

Co-authored-by: julia <julia@zed.dev>

crates/proto/src/proto.rs

@@ -451,6 +451,7 @@ messages!(
     (GetRemotes, Background),
     (GetRemotesResponse, Background),
     (Pull, Background),
+    (RemoteMessageResponse, Background),
 );
 
 request_messages!(
@@ -589,10 +590,10 @@ request_messages!(
     (GitReset, Ack),
     (GitCheckoutFiles, Ack),
     (SetIndexText, Ack),
-    (Push, Ack),
-    (Fetch, Ack),
+    (Push, RemoteMessageResponse),
+    (Fetch, RemoteMessageResponse),
     (GetRemotes, GetRemotesResponse),
-    (Pull, Ack),
+    (Pull, RemoteMessageResponse),
 );
 
 entity_messages!(