getEnvironmentFromUrl function
Helper function to get environment from URL (for debugging purposes)
Implementation
GoMailerEnvironment? getEnvironmentFromUrl(String url) {
if (url.contains('go-mailer.com')) return GoMailerEnvironment.production;
if (url.contains('gm-g7.xyz')) return GoMailerEnvironment.staging;
if (url.contains('gm-g6.xyz')) return GoMailerEnvironment.development;
return null; // Custom URL
}