Model aliases openai merged

Model Alias	Maps to	Model Alias	Maps to
`chatgpt` *	`gpt-5.3-chat-latest`	`gpt54` *	`gpt-5.4`
`codex` *	`gpt-5.3-codex`	`gpt54-mini` *	`gpt-5.4-mini`
`gpt51` *	`gpt-5.1`	`gpt54-nano` *	`gpt-5.4-nano`
`gpt52` *	`gpt-5.2`