WebSocket connect logs print the full base URL, leaking credentials embedded in openai_base_url

Summary

The Responses WebSocket transport logs the full connection URL on connect, success, and failure. When openai_base_url (or a model_providers.*.base_url) carries a credential — a capability-URL path segment, or URL userinfo — that secret ends up verbatim in the CLI's stderr / log output.

Local proxies and gateways in front of Codex commonly authenticate exactly this way, because the built-in openai provider's root openai_base_url override cannot carry a custom header, so the URL itself is the only place a local admission token can live (e.g. http://127.0.0.1:10100/t/<token>/v1).

Where

codex-rs/codex-api/src/endpoint/responses_websocket.rs (connect_websocket, as of 3d4d253f8f4a):

• https://github.com/openai/codex/blob/3d4d253f8f4a/codex-rs/codex-api/src/endpoint/responses_websocket.rs#L495 — info!("connecting to websocket: {url}")
• info!("successfully connected to websocket: {url}, headers: {:?}", …) a few lines below
• https://github.com/openai/codex/blob/3d4d253f8f4a/codex-rs/codex-api/src/endpoint/responses_websocket.rs#L516 — error!("failed to connect to websocket: {err}, url: {url}")

The error! site is the worst of the three: it fires at default log level on every WS fallback (e.g. a gateway answering 426 Upgrade Required), so the secret lands in plain stderr during otherwise-normal operation, not just under RUST_LOG debugging.

Reproduction

1. Point Codex at any local endpoint whose URL embeds a secret, e.g. in ~/.codex/config.toml:

``toml
openai_base_url = "http://127.0.0.1:10100/t/SECRET-TOKEN/v1"
``

1. Have the endpoint reject the WebSocket upgrade (HTTP 426) so Codex falls back to HTTP.
2. Run codex exec "hi". Observed on codex-cli 0.147.0:

``
ERROR codex_api::endpoint::responses_websocket: failed to connect to websocket: HTTP error: 426 Upgrade Required, url: ws://127.0.0.1:10100/t/SECRET-TOKEN/v1/responses
``

The HTTP fallback then works fine — which makes it easy to copy this stderr into bug reports, CI logs, or shared terminals without noticing the token.

Suggested fix

Redact the URL before logging at these sites: strip userinfo and query, and mask path segments (or at least log only scheme://host:port). Something like a small redacted_url(&Url) -> String helper used by all three call sites; map_ws_error may want the same treatment if the URL is embedded into the returned error string.

Happy to send a PR if that shape sounds right.