chore: prefer returning Err to expect() (#2389)

Letting the caller deal with `Err` seems preferable to using `expect()`
(which would `panic!()`), particularly given that the function already
returns `Result`.









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* #2399
* #2398
* #2396
* #2395
* #2394
* #2393
* __->__ #2389

Author: bolinfest

codex-rs/login/src/server.rs

@@ -59,10 +59,9 @@ pub struct LoginServer {
 
 impl LoginServer {
     pub fn block_until_done(self) -> io::Result<()> {
-        #[expect(clippy::expect_used)]
         self.server_handle
             .join()
-            .expect("can't join on the server thread")
+            .map_err(|err| io::Error::other(format!("login server thread panicked: {err:?}")))?
     }
 
     pub fn cancel(&self) {