fix(api): never cache anchor=latest windows as immutable [CI]

backend/src/MoShiro.Backend.Api/Common/QueryHelpers.cs

@@ -32,7 +32,10 @@ internal static class QueryHelpers
     /// </summary>
     public static IResult? ApplyCaching(HttpContext http, QueryRange range, long nowMs, string material)
     {
-        bool closed = !range.IsRelative && range.RequestedToMs < nowMs - (2 * Steps.Minute);
+        // anchor=latest 的相对时间段会被换成以“最后一个样本”为终点的绝对区间：线路停过一阵再恢复时，同一个地址的内容就会变，
+        // 不能当成“已经结束的区间”永久缓存（浏览器会把某一刻的旧数据一直留着，页面上就是线路条不更新）。
+        bool anchored = string.Equals(http.Request.Query["anchor"], "latest", StringComparison.OrdinalIgnoreCase);
+        bool closed = !anchored && !range.IsRelative && range.RequestedToMs < nowMs - (2 * Steps.Minute);
         if (!closed)
         {
             http.Response.Headers.CacheControl = "no-store";