Make the OAuth callback bind host configurable for containerized deployments

[den3110]

Summary

The OAuth callback listener is hardcoded to loopback, which makes ChatGPT login impossible whenever the browser runs outside the process's network namespace — containers being the common case. Making the bind host configurable is enough to support it.

Detail

src-tauri/src/auth/oauth_server.rs:147:

let server = match Server::http(format!("127.0.0.1:{DEFAULT_PORT}")) {

The redirect target is http://localhost:{port}/auth/callback. When codex-web runs in a container, localhost:1455 in the user's browser is the host's loopback, while the listener sits on the container's — so the callback never lands and complete_login waits forever.

The UI already warns about this ("OAuth login must finish on the same host machine because the callback redirects to localhost"), so the limitation is known — this is a request to lift it rather than a bug report.

Suggested change

Keep loopback as the default and allow opting into a wider bind:

let bind_host = std::env::var("CODEX_SWITCHER_OAUTH_HOST")
    .unwrap_or_else(|_| "127.0.0.1".to_string());

let server = match Server::http(format!("{bind_host}:{DEFAULT_PORT}")) {

The deployment then publishes the callback port on host loopback, e.g. in Docker:

ports:
  - "127.0.0.1:1455:1455"
environment:
  CODEX_SWITCHER_OAUTH_HOST: 0.0.0.0

Verified working: browser -> auth.openai.com -> redirect to localhost:1455 (host) -> Docker forwards -> container listener logs [OAuth] Received callback request, and login completes.

Worth noting the existing random-port fallback (Server::http("127.0.0.1:0")) can't be published ahead of time in a container, so a clear error may be preferable to an unreachable port there.

Version: v0.2.12