Restructure RPC state to also keep track of remote worktrees on guests

zed-rpc/src/peer.rs

@@ -29,7 +29,7 @@ type BoxedReader = Pin<Box<dyn AsyncRead + 'static + Send>>;
 pub struct ConnectionId(u32);
 
 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
-pub struct PeerId(u32);
+pub struct PeerId(pub u32);
 
 struct Connection {
     writer: Mutex<MessageStream<BoxedWriter>>,

zed-rpc/src/proto.rs

@@ -74,6 +74,7 @@ request_message!(OpenWorktree, OpenWorktreeResponse);
 request_message!(OpenBuffer, OpenBufferResponse);
 message!(CloseBuffer);
 message!(UpdateBuffer);
+message!(RemoveGuest);
 
 /// A stream of protobuf messages.
 pub struct MessageStream<T> {