pub fn load_credentials() -> Result<AtlassianCredentials>Expand description
Loads Atlassian credentials from environment variables or settings.json.
Checks environment variables first, then falls back to the settings file.
The global --instance flag (propagated to ATLASSIAN_INSTANCE_OVERRIDE_ENV)
overrides the configured instance URL for every command; a blank value is
ignored. Callers that carry their own explicit override should call
load_credentials_with_instance directly.