feat: 站点单页、时间线导入与行级 BBCode 短代码

首页右栏接入单页入口与公告置顶/全部页；Markdown 编辑器支持可视化时间线与 Git 导入；隐藏块改为 [hide]/[timeline] 命名闭合，并修复单页/公告 GORM 更新只改 updated_at 的问题。

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

frontend/app/page.tsx

@@ -11,6 +11,7 @@ import {
 } from "@/lib/api";
 import { authCookieHeader } from "@/lib/cookies";
 import { getMeCached, getPublicSettingsCached } from "@/lib/serverData";
+import { isAdminOrAbove } from "@/lib/roles";
 import Pagination from "@/components/Pagination";
 import PostRow from "@/components/PostRow";
 import FeedTabs, { type FeedSort } from "@/components/home/FeedTabs";
@@ -110,6 +111,8 @@ export default async function HomePage({ searchParams }: HomePageProps) {
   ]);
   const user = me.user;
   const boards = overview?.boards ?? [];
+  const canManageAnnouncements = !!user && isAdminOrAbove(user.role);
+  const sidebarPages = overview?.sidebar_pages ?? [];
   const activeBoard = boards.find((b) => b.id === boardId) || boardSidebar?.board || null;
   const showBoardPanels = boardId > 0 && !isSearch;
   // boardId 有效但接口失败 → 显示简卡；成功则板级右栏；否则全站右栏
@@ -235,6 +238,8 @@ export default async function HomePage({ searchParams }: HomePageProps) {
               newUsers={overview.new_users}
               checkin={overview.checkin ?? undefined}
               allowComments={allowComments}
+              canManageAnnouncements={canManageAnnouncements}
+              sidebarPages={sidebarPages}
             />
           )
         )}
@@ -266,6 +271,8 @@ export default async function HomePage({ searchParams }: HomePageProps) {
               newUsers={overview.new_users}
               checkin={overview.checkin ?? undefined}
               allowComments={allowComments}
+              canManageAnnouncements={canManageAnnouncements}
+              sidebarPages={sidebarPages}
             />
           </div>
         )