feat: EOD 23:15 seal + midnight seed shell for video/fans

Move daily snapshot/fans to 23:15 and add 00:01 seed that clones
last_completed ok=1 rows into today without advancing completed.
Evening runs force through seed markers; growth previous is per-aid
adjacent. Home shows short-update clock + 全站数据 date, and 收录视频
counts.

reaction_board/web/static/views/system.js

@@ -94,6 +94,7 @@ export async function renderSystem(root) {
     <section class="panel">
       ${sectionHeader("预计下次运行")}
       <div class="status-grid status-row-4">
+        <div><span>午夜落盘克隆</span><strong>${running.snapshot_seed ? "运行中" : escapeHtml(formatDateTime(next.snapshot_seed))}</strong></div>
         <div><span>咻咻满粉丝数更新</span><strong>${running.fans ? "运行中" : escapeHtml(formatDateTime(next.fans))}</strong></div>
         <div><span>视频数据快照 + UP 信息</span><strong>${running.snapshot ? "运行中" : escapeHtml(formatDateTime(next.snapshot))}</strong></div>
         <div><span>新视频小时同步</span><strong>${running.snapshot_recent ? "运行中" : escapeHtml(formatDateTime(next.snapshot_recent))}</strong></div>