fix: remove shutdown_flag param to run_login_server() (#2399)

In practice, this was always passed in as `None`, so eliminated the
param and updated all the call sites.

---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/2399).
* __->__ #2399
* #2398
* #2396
* #2395
* #2394
* #2393
* #2389

codex-rs/cli/src/login.rs

@@ -14,7 +14,7 @@ use std::path::PathBuf;
 
 pub async fn login_with_chatgpt(codex_home: PathBuf) -> std::io::Result<()> {
     let opts = ServerOptions::new(codex_home, CLIENT_ID.to_string());
-    let server = run_login_server(opts, None)?;
+    let server = run_login_server(opts)?;
 
     eprintln!(
         "Starting local login server on http://localhost:{}.\nIf your browser did not open, navigate to this URL to authenticate:\n\n{}",

codex-rs/login/src/server.rs

@@ -77,10 +77,7 @@ impl ShutdownHandle {
     }
 }
 
-pub fn run_login_server(
-    opts: ServerOptions,
-    shutdown_flag: Option<Arc<tokio::sync::Notify>>,
-) -> io::Result<LoginServer> {
+pub fn run_login_server(opts: ServerOptions) -> io::Result<LoginServer> {
     let pkce = generate_pkce();
     let state = opts.force_state.clone().unwrap_or_else(generate_state);
 
@@ -118,7 +115,7 @@ pub fn run_login_server(
         })
     };
 
-    let shutdown_notify = shutdown_flag.unwrap_or_else(|| Arc::new(tokio::sync::Notify::new()));
+    let shutdown_notify = Arc::new(tokio::sync::Notify::new());
     let server_handle = {
         let shutdown_notify = shutdown_notify.clone();
         let server = server.clone();

codex-rs/login/tests/login_server_e2e.rs

@@ -101,7 +101,7 @@ async fn end_to_end_login_flow_persists_auth_json() {
         open_browser: false,
         force_state: Some(state),
     };
-    let server = run_login_server(opts, None).unwrap();
+    let server = run_login_server(opts).unwrap();
     let login_port = server.actual_port;
 
     // Simulate browser callback, and follow redirect to /success
@@ -159,7 +159,7 @@ async fn creates_missing_codex_home_dir() {
         open_browser: false,
         force_state: Some(state),
     };
-    let server = run_login_server(opts, None).unwrap();
+    let server = run_login_server(opts).unwrap();
     let login_port = server.actual_port;
 
     let client = reqwest::Client::new();

codex-rs/mcp-server/src/codex_message_processor.rs

@@ -154,7 +154,7 @@ impl CodexMessageProcessor {
             Error(JSONRPCErrorError),
         }
 
-        let reply = match run_login_server(opts, None) {
+        let reply = match run_login_server(opts) {
             Ok(server) => {
                 let login_id = Uuid::new_v4();
                 let shutdown_handle = server.cancel_handle();

codex-rs/tui/src/onboarding/auth.rs

@@ -281,7 +281,7 @@ impl AuthModeWidget {
     fn start_chatgpt_login(&mut self) {
         self.error = None;
         let opts = ServerOptions::new(self.codex_home.clone(), CLIENT_ID.to_string());
-        let server = run_login_server(opts, None);
+        let server = run_login_server(opts);
         match server {
             Ok(child) => {
                 let auth_url = child.auth_url.clone();