export function asNumber(value: string | undefined, fallback: number): number {
  const n = Number(value);
  return Number.isFinite(n) ? n : fallback;
}
export function asBoolean(value: string | undefined, fallback: boolean): boolean {
  if (value === undefined) return fallback;
  return ["1", "true", "yes", "on"].includes(String(value).toLowerCase());
}
export function required(name: string, value: string | undefined): string {
  if (!value) throw new Error(`Missing required environment variable: ${name}`);
  return value;
}