Function codex_models_path 

pub fn codex_models_path(client_version: &str) -> String

Build the broker-relative path for the ChatGPT backend Codex catalog endpoint, including the required client_version query (matches official Codex). An empty client_version falls back to the pinned CODEX_CLIENT_VERSION — never SynapsCLI’s own crate version, which the backend would reject with an empty catalog.