feat: 实时消息与管理端运营能力

新增群聊/私信与公共 WebSocket 总线，站长用户内容档案，并将通知与待审角标改为推送驱动；同步精简管理仪表盘并修复主题换肤 DOM 冲突。

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

frontend/components/home/FeedNewTip.tsx

@@ -0,0 +1,75 @@
+"use client";
+
+import { useEffect, useState } from "react";
+import { useRouter } from "next/navigation";
+import { ArrowUp } from "lucide-react";
+import {
+  realtime,
+  RT_FEED_CHANGED,
+  type RtFeedChangedData,
+} from "@/lib/realtime";
+import type { FeedSort } from "@/components/home/FeedTabs";
+
+interface FeedNewTipProps {
+  sort: FeedSort;
+  boardId?: number;
+  page?: number;
+  userId: number;
+}
+
+// 帖子流「有新内容」提示（三期）：WS feed:changed → tip → 点击 refresh SSR
+export default function FeedNewTip({
+  sort,
+  boardId = 0,
+  page = 1,
+  userId,
+}: FeedNewTipProps) {
+  const router = useRouter();
+  const [visible, setVisible] = useState(false);
+
+  useEffect(() => {
+    // 第 2+ 页与推荐帖不订阅展示（推荐不随新帖/新评变化）
+    if (page !== 1 || sort === "recommended") {
+      setVisible(false);
+      return;
+    }
+
+    const off = realtime.on<RtFeedChangedData>(RT_FEED_CHANGED, (data) => {
+      if (!data || typeof data.post_id !== "number") return;
+      // 忽略自己刚发布的内容，避免回首页又弹 tip
+      if (data.actor_id === userId) return;
+      if (boardId > 0 && data.board_id !== boardId) return;
+      // 「新帖子」tab 只关心新帖；「新评论」tab 接受帖与评
+      if (sort === "new" && data.kind !== "post") return;
+      if (data.kind !== "post" && data.kind !== "comment") return;
+      setVisible(true);
+    });
+    return off;
+  }, [sort, boardId, page, userId]);
+
+  if (!visible || page !== 1 || sort === "recommended") return null;
+
+  const handleClick = () => {
+    setVisible(false);
+    router.refresh();
+    window.scrollTo({ top: 0, behavior: "smooth" });
+  };
+
+  return (
+    <div className="px-3 sm:px-4 pb-2.5">
+      <button
+        type="button"
+        onClick={handleClick}
+        className="j13-feed-new-tip w-full inline-flex items-center justify-center gap-1.5 py-2 px-3 text-[13px] font-semibold rounded-[var(--r-sm)] transition-colors"
+        style={{
+          color: "var(--accent)",
+          background: "var(--accent-soft)",
+          border: "1px solid var(--nav-active-line, var(--accent))",
+        }}
+      >
+        <ArrowUp size={14} aria-hidden />
+        有新内容
+      </button>
+    </div>
+  );
+}