fix(forum): align forum pages with the reference layout

- cards: restore the shared card shell, add author follow/message actions,
  score group, last-reply meta and reference plate header actions
- home: desktop left tab rail, widget-only sidebar, reference load-more markup
- plate: 1-based tabs, reference defaults (全部/推荐/最新回复/热门/精华)
- post: fixed action rail, score footer, author card, h1 article title
- quick publish: plate selector moved into the submit row like the reference

tests/forum/pages-contract.test.cjs

@@ -30,7 +30,7 @@ test('post detail pages use the reference article shell', () => {
   const post = read('src/Forum/PostView.php')
   const template = read('templates/pages/page-forum-post.php')
   assert.match(template, /PostView::render\(\)/)
-  for (const token of ['fixed-wrap single-wrap', 'fixed-wrap-content', 'forum-single-cover', 'breadcrumb', 'id="article"', 'article zib-widget forum-article', 'article-header clearfix', 'forum-article-meta', 'wp-posts-content', 'article-tags', 'forum-article-footer', 'footer-actions', 'vote-box forum-vote', 'comments-card']) {
+  for (const token of ['fixed-wrap single-wrap', 'fixed-wrap-content', 'forum-single-cover', 'breadcrumb', 'id="article"', 'article jio-panel forum-article', 'article-header clearfix', 'forum-article-meta', 'wp-posts-content', 'article-tags', 'forum-article-footer', 'footer-actions', 'vote-box forum-vote', 'comments-card']) {
     assert.ok(post.includes(token), `post page missing ${token}`)
   }
   // Banners, permissions and actions stay server-side.