feat(web): include removed in visible stats; cover bang badge

站内展示/统计统一 VISIBLE（含 removed）：热度、UP 列表、总览
active_ups/初导入计数、说明页粉丝覆盖、黑名单视频数。采集队列仍
只 active/unfaved。失效片封面右上角感叹号徽标，点击/tap 提示
「该视频已失效」；手动/候选入库仍可复活 removed→active。

reaction_board/web/static/style.css

@@ -388,6 +388,32 @@ a.live-chip:hover { border-color: color-mix(in srgb, var(--accent) 55%, var(--bo
   background: color-mix(in srgb, var(--accent) 70%, transparent);
   color: #fff;
 }
+
+.detail-cover-wrap { position: relative; }
+.cover-removed-mark {
+  position: absolute;
+  z-index: 2;
+  top: 6px;
+  right: 6px;
+  display: grid;
+  place-items: center;
+  width: 22px;
+  height: 22px;
+  padding: 0;
+  border: 0;
+  border-radius: 999px;
+  background: color-mix(in srgb, var(--warning) 82%, #1a1208);
+  color: #fff8f0;
+  font-size: 13px;
+  font-weight: 700;
+  line-height: 1;
+  cursor: help;
+  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.35);
+}
+.cover-removed-mark:focus-visible {
+  outline: 2px solid var(--accent);
+  outline-offset: 2px;
+}
 .cover-duration {
   position: absolute;
   z-index: 1;