Function credits_balance 

async fn credits_balance(
    client: &Client,
    base_url: &str,
    bearer: &str,
) -> Option<f64>

The account’s remaining credit pool, or None when the fetch or decode fails for any reason, or the 200 carries no data envelope - each logged with its own cause. The balance is auxiliary, and the /v1/key data the panel also renders must stand even when this endpoint is unavailable.