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/components/FeedHeader.tsx

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+import { Button } from '@/components/ui/button';
+import { Plus, Settings } from 'lucide-react';
+import { useNavigate } from 'react-router-dom';
+import type { Board, ForumStats } from '../api/types';
+import { useAuth } from '../hooks/useAuth';
+
+interface Props {
+  boardId: number;
+  keyword: string;
+  boards: Board[];
+  stats: ForumStats | null;
+  postTotal: number;
+}
+
+export default function FeedHeader({ boardId, keyword, boards, stats, postTotal }: Props) {
+  const nav = useNavigate();
+  const { user, loading: authLoading } = useAuth();
+  const board = boards.find(b => b.id === boardId);
+
+  const title = keyword
+    ? `搜索：${keyword}`
+    : (boardId && board ? board.name : '全部帖子');
+
+  const hint = keyword
+    ? `找到 ${postTotal} 篇相关帖子`
+    : boardId && board
+      ? (board.description || '欢迎在本板块交流讨论')
+      : '姜十三论坛 · 拾三一隅，自在交流';
+
+  return (
+    <div className="feed-banner">
+      <div className="feed-banner-row">
+        <div className="feed-banner-title">
+          <h2>{title}</h2>
+          <p>{hint}</p>
+        </div>
+        {!keyword && (
+          <div className="feed-actions flex flex-wrap items-center gap-2">
+            {authLoading ? (
+              <span className="feed-action-slot" aria-hidden />
+            ) : user ? (
+              <Button
+                size="sm"
+                onClick={() => nav(boardId ? `/compose?board=${boardId}` : '/compose')}
+              >
+                <Plus />
+                {boardId ? '在此发帖' : '发布帖子'}
+              </Button>
+            ) : (
+              <Button size="sm" onClick={() => nav('/login')}>登录参与</Button>
+            )}
+            {!authLoading && user?.role === 'admin' && (
+              <Button size="sm" variant="outline" onClick={() => nav('/boards')}>
+                <Settings />
+                管理板块
+              </Button>
+            )}
+          </div>
+        )}
+      </div>
+      <div className="feed-stats">
+        <span>会员 <strong>{stats?.users ?? '—'}</strong></span>
+        <span>帖子 <strong>{stats?.posts ?? '—'}</strong></span>
+        <span>板块 <strong>{stats?.boards ?? '—'}</strong></span>
+      </div>
+    </div>
+  );
+}