feat(growth): same-day 1-day baselines for new videos

Let 1-day view growth use a zero baseline for videos published today, and the first successful sample for older videos ingested today, without mixing those into 7/30-day rankings.

reaction_board/web/static/views/about.js

@@ -92,7 +92,7 @@ export async function renderAbout(root) {
         <li>B 站不公开完播率与单 P 播放，内容小时是“供给时长”，不是“实际观看时长”。</li>
         <li>多 P 可能让同一用户产生多次播放计数，本站不单独校正，属于已知偏差。</li>
         <li>粉丝数可能包含不活跃账号；粉丝快照暂不参与任何榜单。</li>
-        <li>样本不足（少于 2 天快照、单视频 UP）会显示提示，不伪造 0。</li>
+        <li>近 7/30 日增长仍要跨日快照。近 1 日：当日发布按 0 起算；更早发布的新入库按入库时播放量起算，需当天至少两次采样。样本不足时显示提示，不伪造 0。</li>
       </ul>
     </section>