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/components/MarkdownBody.tsx

@@ -1,7 +1,10 @@
+import type { ReactNode } from "react";
 import type { Components } from "react-markdown";
 import { renderMarkdownToReact } from "@/components/markdown/renderMarkdown";
-import { splitHideSegments, type HideKind } from "@/lib/hideBlocks";
+import { splitContentSegments } from "@/lib/directiveBlocks";
+import type { HideKind } from "@/lib/hideBlocks";
 import MdHideBlock from "@/components/markdown/MdHideBlock";
+import MdTimeline from "@/components/markdown/MdTimeline";
 
 type MarkdownBodyProps = {
   content: string;
@@ -9,20 +12,23 @@ type MarkdownBodyProps = {
   components?: Components;
   /** 详情页解锁门禁需要 */
   postId?: number;
+  /** 登录跳转（公告等无 postId 时） */
+  loginHref?: string;
   loggedIn?: boolean;
 };
 
 /**
- * 站点统一 Markdown 渲染（服务端）：GFM + Shiki；支持 :::hide 内嵌块。
+ * 站点统一 Markdown 渲染（服务端）：GFM + Shiki；支持 [hide] / [timeline]。
  */
 export default async function MarkdownBody({
   content,
   className = "prose-content",
   components,
   postId,
+  loginHref,
   loggedIn = false,
 }: MarkdownBodyProps) {
-  const segs = splitHideSegments(content || "");
+  const segs = splitContentSegments(content || "");
   const nodes = [];
   for (let i = 0; i < segs.length; i++) {
     const seg = segs[i];
@@ -33,6 +39,25 @@ export default async function MarkdownBody({
       );
       continue;
     }
+    if (seg.type === "timeline") {
+      const bodies: ReactNode[] = [];
+      for (let j = 0; j < seg.items.length; j++) {
+        const it = seg.items[j];
+        if (!it.body.trim()) {
+          bodies.push(null);
+          continue;
+        }
+        bodies.push(await renderMarkdownToReact(it.body, components));
+      }
+      nodes.push(
+        <MdTimeline
+          key={`tl-${i}`}
+          items={seg.items}
+          renderBody={(_it, idx) => bodies[idx]}
+        />
+      );
+      continue;
+    }
     const kind = seg.kind as HideKind;
     if (seg.locked) {
       nodes.push(
@@ -42,6 +67,7 @@ export default async function MarkdownBody({
           points={seg.points}
           locked
           postId={postId}
+          loginHref={loginHref}
           loggedIn={loggedIn}
         />
       );