估算模型月度费用和分级路由

只是写法示意，不是完整程序。

// ANS 大模型月度 API 账单与缓存折扣精算器 (ans-llm-cost.ts)
export function estimateAnsMonthlyLlmCost(dailyReqs: number, inTokens: number, outTokens: number, inPricePerM: number, outPricePerM: number, cacheHitRatio = 0.5) {
  const effectiveInPrice = inPricePerM * (1 - cacheHitRatio * 0.8);
  const dailyUsd = (dailyReqs * (inTokens * effectiveInPrice + outTokens * outPricePerM)) / 1_000_000;
  return { dailyUsd: +dailyUsd.toFixed(2), monthlyUsd: +(dailyUsd * 30).toFixed(2) };
}