Add Codex CLI link to OpenAI section

Author: pharmacist-sabot

README.md

@@ -1076,6 +1076,7 @@ See also [About Rust’s Machine Learning Community](https://medium.com/@autumn_
 
 * [0xplaygrounds/rig](https://github.com/0xplaygrounds/rig) - Library for creating agents and modular, scalable LLM-powered applications
 * [64bit/async-openai](https://github.com/64bit/async-openai) [[async-openai](https://crates.io/crates/async-openai)] - Ergonomic Rust bindings for OpenAI API based on OpenAPI spec.
+* [openai/codex](https://github.com/openai/codex) - Codex CLI is a coding agent from OpenAI that runs locally.
 * [openai/harmony](https://github.com/openai/harmony) [[openai-harmony](https://crates.io/crates/openai-harmony/0.0.3)] - Renderer for the harmony response format to be used with gpt-oss.
 * [zurawiki/tiktoken-rs](https://github.com/zurawiki/tiktoken-rs) [[tiktoken-rs](https://crates.io/crates/tiktoken-rs)] - Library for tokenizing text with OpenAI models using tiktoken. [![CI](https://github.com/zurawiki/tiktoken-rs/actions/workflows/ci.yml/badge.svg)](https://github.com/zurawiki/tiktoken-rs/actions/workflows/ci.yml)