Validated JML configuration object
if required configuration is missing or invalid
// Set environment variables first (or use .env file)
process.env.JIRA_BASE_URL = 'https://jira.company.com';
process.env.JIRA_PAT = 'your-token';
const config = loadConfig();
console.log(config.baseUrl); // https://jira.company.com
Loads configuration from environment variables with validation.