Function load_with_env_overrides 

pub fn load_with_env_overrides(
    path: Option<&Path>,
) -> Result<Config, ConfigError>

Load config with env-var overrides applied on top of file values. Returns Config::default() if path is None or the file doesn’t exist.

Env var precedence per Client spec rev1 §5:

• CLEANLIBRARY_API_KEY → auth.api_key
• CLEANLIBRARY_ENDPOINT → endpoint.url
• CLEANLIBRARY_API_VERSION → endpoint.api_version
• CLEANLIBRARY_TELEMETRY (0/1/true/false) → telemetry.enabled