Suppress console windows when spawning the code-mode host on Windows (#48138)

Set `CREATE_NO_WINDOW` when launching the code-mode host on Windows so the
child process does not create a console window.

GitOrigin-RevId: ce0d04d7f516d137bcaf5206140aaeaa23334022

codex-rs/code-mode/src/remote_session/connection.rs

@@ -158,6 +158,8 @@ impl Connection {
         let mut command = Command::new(host_program);
         #[cfg(unix)]
         command.process_group(0);
+        #[cfg(windows)]
+        command.creation_flags(/*flags*/ 0x0800_0000); // CREATE_NO_WINDOW
         command
             .stdin(Stdio::piped())
             .stdout(Stdio::piped())