初始提交：姜十三论坛 Jiang13 Forum

轻量自用论坛，Go 单二进制 + React SPA 内嵌 + SQLite。

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

frontend/src/utils/content.ts

@@ -0,0 +1,20 @@
+/** @用户名 高亮（仅用于评论正文中用户主动输入的 @） */
+export function highlightMentions(text: string, _onClick?: (name: string) => void): string {
+  return text
+    .replace(/&/g, '&')
+    .replace(/</g, '&lt;')
+    .replace(/>/g, '&gt;')
+    // innerHTML 解析会吞掉换行，需转为 <br>
+    .replace(/\n/g, '<br>')
+    .replace(/@([\w\u4e00-\u9fa5_-]+)/g, '<span class="mention">@$1</span>');
+}
+
+export function formatTime(iso: string) {
+  const d = new Date(iso);
+  const now = new Date();
+  const diff = (now.getTime() - d.getTime()) / 1000;
+  if (diff < 60) return '刚刚';
+  if (diff < 3600) return `${Math.floor(diff / 60)}分钟前`;
+  if (diff < 86400) return `${Math.floor(diff / 3600)}小时前`;
+  return `${d.getMonth() + 1}-${d.getDate()} ${String(d.getHours()).padStart(2, '0')}:${String(d.getMinutes()).padStart(2, '0')}`;
+}