fix: 空评论列表 500，并完善撤回审计与角色说明

空切片 JSON 统一为数组；撤回保留正文供站长阅读，成员侧居中提示与重新编辑；头像支持拖放；角色弹窗补全职责说明并汇入封禁。

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/components/Header.tsx

@@ -27,6 +27,7 @@ import { isStaff } from "@/lib/roles";
 import { onUserUpdate, onForceLogout } from "@/lib/userEvents";
 import { realtime, RT_CHAT_UNREAD } from "@/lib/realtime";
 import type { RtChatUnreadData } from "@/lib/realtime";
+import { onDocumentVisible } from "@/lib/visibilityReconcile";
 import NotificationBell from "./NotificationBell";
 import Avatar from "./Avatar";
 
@@ -112,29 +113,26 @@ export default function Header({
     return off;
   }, [user, pathname]);
 
-  // 会话内已读后主动对账（ChatRoomClient 派发）
+  // 会话内已读 / 回前台：合并对账（短时间多次 markRead 只打一次 summary）
   useEffect(() => {
     if (!user) return;
-    const onSync = () => {
+    let debounceTimer: ReturnType<typeof setTimeout> | null = null;
+    const pullSummary = () => {
       apiChatUnreadSummary()
         .then((res) => setChatUnread(res.total || 0))
         .catch(() => {});
     };
+    const onSync = () => {
+      if (debounceTimer) clearTimeout(debounceTimer);
+      debounceTimer = setTimeout(pullSummary, 250);
+    };
     window.addEventListener("j13-chat-unread-sync", onSync);
-    return () => window.removeEventListener("j13-chat-unread-sync", onSync);
-  }, [user]);
-
-  // 切回标签页时重新对账未读
-  useEffect(() => {
-    if (!user) return;
-    const onVisible = () => {
-      if (document.visibilityState !== "visible") return;
-      apiChatUnreadSummary()
-        .then((res) => setChatUnread(res.total || 0))
-        .catch(() => {});
+    const offVisible = onDocumentVisible(pullSummary);
+    return () => {
+      if (debounceTimer) clearTimeout(debounceTimer);
+      window.removeEventListener("j13-chat-unread-sync", onSync);
+      offVisible();
     };
-    document.addEventListener("visibilitychange", onVisible);
-    return () => document.removeEventListener("visibilitychange", onVisible);
   }, [user]);
 
   const handleSearch = (e: React.FormEvent) => {