制定零基预算和现金流计划

只是写法示意，不是完整程序。

// ANS 零基信封预算分配与超支校验核心 (ans-envelope-budget.ts)
export function auditAnsEnvelopeBudget(cashOnHand: number, envelopes: Array<{ name: string; allocated: number; spent: number }>) {
  const totalAllocated = envelopes.reduce((s, e) => s + e.allocated, 0);
  const overspent = envelopes.filter((e) => e.spent > e.allocated).map((e) => e.name);
  return { unallocated: cashOnHand - totalAllocated, isBalanced: totalAllocated <= cashOnHand, overspent };
}