feat: 首页 Go SSR 与 React hydrate 同构，消壳层与帖行闪动

补齐侧栏/右栏图标与徽章、鉴权种子、StaticFeedList，并修正嵌套 a 与标题徽章对齐。

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

frontend/src/components/SiteFooter.tsx

@@ -9,7 +9,7 @@ function FooterSep() {
   return <span className="site-footer__sep" aria-hidden>·</span>;
 }
 
-/** 站点页脚：版权、友链/展柜入口、单页、备案号 */
+/** 站点页脚：版权、友链/展柜入口、单页、备案号（结构与 Go writeSSRFooter 对齐） */
 export default function SiteFooter() {
   const { branding } = useSiteBranding();
   const { footerPages } = useSitePages();
@@ -19,8 +19,42 @@ export default function SiteFooter() {
   const icpURL = branding.icp_beian_url?.trim() || 'https://beian.miit.gov.cn/';
   const showFriendLinks = limits.footer_show_friend_links !== false;
   const showShowcase = !!limits.footer_show_showcase;
-  const hasNavBeforePages = showFriendLinks || showShowcase;
-  const hasNavBeforeIcp = hasNavBeforePages || footerPages.length > 0;
+
+  const navItems: React.ReactNode[] = [];
+  if (showFriendLinks) {
+    navItems.push(
+      <span key="links" className="site-footer__friend">
+        <Link to="/links">友情链接</Link>
+      </span>,
+    );
+  }
+  if (showShowcase) {
+    navItems.push(
+      <span key="showcase" className="site-footer__friend">
+        <Link to="/showcase">开源展柜</Link>
+      </span>,
+    );
+  }
+  for (const p of footerPages) {
+    navItems.push(
+      <span key={p.slug} className="site-footer__friend">
+        <Link to={pagePath(p.slug, limits)}>{p.title}</Link>
+      </span>,
+    );
+  }
+  if (icp) {
+    navItems.push(
+      <a
+        key="icp"
+        href={icpURL}
+        target="_blank"
+        rel="noopener noreferrer"
+        className="site-footer__icp"
+      >
+        {icp}
+      </a>,
+    );
+  }
 
   return (
     <footer className="site-footer">
@@ -38,35 +72,8 @@ export default function SiteFooter() {
         </div>
 
         <nav className="site-footer__nav" aria-label="站点链接">
-          {showFriendLinks && (
-            <span className="site-footer__friend">
-              <Link to="/links">友情链接</Link>
-            </span>
-          )}
-          {showShowcase && (
-            <span className="site-footer__friend">
-              {showFriendLinks && <FooterSep />}
-              <Link to="/showcase">开源展柜</Link>
-            </span>
-          )}
-          {footerPages.map((p, i) => (
-            <span key={p.slug} className="site-footer__friend">
-              {(hasNavBeforePages || i > 0) && <FooterSep />}
-              <Link to={pagePath(p.slug, limits)}>{p.title}</Link>
-            </span>
-          ))}
-          {icp && (
-            <>
-              {hasNavBeforeIcp && <FooterSep />}
-              <a
-                href={icpURL}
-                target="_blank"
-                rel="noopener noreferrer"
-                className="site-footer__icp"
-              >
-                {icp}
-              </a>
-            </>
+          {navItems.flatMap((node, i) =>
+            i === 0 ? [node] : [<FooterSep key={`sep-${i}`} />, node],
           )}
         </nav>
       </div>