Loads the saved VALD API configuration from the user's config file and retrieves sensitive credentials securely from the system keyring.
load_credentials(verbose = TRUE)Invisibly returns TRUE if credentials and configuration were loaded successfully, FALSE otherwise.
Logical; if TRUE, prints messages on load status (default FALSE). Internal function (not designed to be used directly by end users)
Also ensures that API endpoints are kept up to date for the current package version (e.g. when new endpoints are added), and persists any repaired endpoint configuration back to disk (non-sensitive fields only).