feat: 管理端板块管理与旧版数据导入，补充部署运营文档

- 新增管理端板块管理页面与后端接口（admin_board）
- 新增旧版数据导入：legacyimport 服务、导入面板、importusers 命令行工具
- 聊天用户卡片、板块图标等 UI 组件与界面优化
- 补充 about/公告/1Panel 部署等文档
- gitignore 排除 dist/ 构建产物与 .agents/ 本地工具目录

frontend/app/admin/boards/page.tsx

@@ -0,0 +1,33 @@
+import type { Metadata } from "next";
+import { cookies } from "next/headers";
+import { authCookieHeader } from "@/lib/cookies";
+import { fetchAdminBoards, type AdminBoard } from "@/lib/api";
+import { getMeCached } from "@/lib/serverData";
+import { isOwner } from "@/lib/roles";
+import Forbidden from "../Forbidden";
+import BoardsAdmin from "./BoardsAdmin";
+
+export const metadata: Metadata = {
+  title: "板块管理",
+};
+
+export default async function AdminBoardsPage() {
+  const cookie = authCookieHeader(await cookies());
+  const me = await getMeCached(cookie || undefined);
+
+  // 仅站长可管理板块
+  if (!me.user || !isOwner(me.user.role)) {
+    return <Forbidden text="板块管理仅站长可操作。" />;
+  }
+
+  let initial: AdminBoard[] | null = null;
+  let initError = "";
+  try {
+    const r = await fetchAdminBoards(cookie || undefined);
+    initial = r.boards ?? [];
+  } catch (e) {
+    initError = e instanceof Error ? e.message : "获取板块列表失败";
+  }
+
+  return <BoardsAdmin initial={initial} initError={initError} />;
+}