remote server: Do not spawn server when proxy reconnects (#18864)

This ensures that we only ever reconnect to a running server and not
spawn a new server with no state.

This avoids the problem of the server process crashing, `proxy`
reconnecting, starting a new server, and the user getting errors like
"unknown buffer id: ...".

Release Notes:

- N/A

---------

Co-authored-by: Bennet Bo Fenner <bennet@zed.dev>

crates/remote/src/remote.rs

@@ -1,5 +1,6 @@
 pub mod json_log;
 pub mod protocol;
+pub mod proxy;
 pub mod ssh_session;
 
 pub use ssh_session::{