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/announcement/[id]/page.tsx

@@ -1,9 +1,12 @@
 import type { Metadata } from "next";
 import Link from "next/link";
+import { cookies } from "next/headers";
 import { notFound } from "next/navigation";
 import { ChevronRight, Megaphone } from "lucide-react";
 import { fetchAnnouncementDetail } from "@/lib/api";
+import { authCookieHeader } from "@/lib/cookies";
 import { formatDate } from "@/lib/format";
+import { getMeCached } from "@/lib/serverData";
 import MarkdownBody from "@/components/MarkdownBody";
 
 interface PageProps {
@@ -28,10 +31,15 @@ export async function generateMetadata({ params }: PageProps): Promise<Metadata>
 
 export default async function AnnouncementPage({ params }: PageProps) {
   const { id } = await params;
-  const data = await fetchAnnouncementDetail(id).catch(() => null);
+  const cookie = authCookieHeader(await cookies());
+  const [data, me] = await Promise.all([
+    fetchAnnouncementDetail(id, cookie || undefined).catch(() => null),
+    getMeCached(cookie || undefined),
+  ]);
   if (!data) notFound();
 
   const a = data.announcement;
+  const loginHref = `/login?redirect=${encodeURIComponent(`/announcement/${id}`)}`;
   const jsonLd = {
     "@context": "https://schema.org",
     "@type": "Article",
@@ -55,12 +63,21 @@ export default async function AnnouncementPage({ params }: PageProps) {
           首页
         </Link>
         <ChevronRight size={13} />
-        <span style={{ color: "var(--accent)" }}>站点公告</span>
+        <Link href="/announcements" className="hover:text-[var(--accent)] transition-colors">
+          站点公告
+        </Link>
+        <ChevronRight size={13} />
+        <span className="truncate" style={{ color: "var(--accent)" }}>
+          {a.title}
+        </span>
       </nav>
 
       <article className="panel p-6 sm:p-8">
         <div className="flex items-center justify-between gap-3 flex-wrap">
-          <span className={`j13-anno-tag is-${a.tag_color}`}>{a.tag}</span>
+          <div className="flex items-center gap-2 flex-wrap">
+            {a.pinned ? <span className="badge-pin">置顶</span> : null}
+            <span className={`j13-anno-tag is-${a.tag_color}`}>{a.tag}</span>
+          </div>
           <time className="meta text-[12px] tabular-nums" dateTime={a.created_at}>
             {formatDate(a.created_at)}
           </time>
@@ -77,7 +94,11 @@ export default async function AnnouncementPage({ params }: PageProps) {
           className="mt-5 pt-5"
           style={{ borderTop: "1px solid var(--line)" }}
         >
-          <MarkdownBody content={a.content} />
+          <MarkdownBody
+            content={a.content}
+            loggedIn={!!me.user}
+            loginHref={loginHref}
+          />
         </div>
       </article>