Add codex login --api-key (#1759)

Allow setting the API key via `codex login --api-key`

codex-rs/cli/src/proto.rs

@@ -36,7 +36,7 @@ pub async fn run_main(opts: ProtoCli) -> anyhow::Result<()> {
         .map_err(anyhow::Error::msg)?;
 
     let config = Config::load_with_cli_overrides(overrides_vec, ConfigOverrides::default())?;
-    let auth = load_auth(&config.codex_home)?;
+    let auth = load_auth(&config.codex_home, true)?;
     let ctrl_c = notify_on_sigint();
     let CodexSpawnOk { codex, .. } = Codex::spawn(config, auth, ctrl_c.clone()).await?;
     let codex = Arc::new(codex);