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/FeedSortBar.tsx

@@ -79,7 +79,12 @@ export function feedSortLabel(sort: FeedSort, tabs?: FeedSortTab[] | null): stri
   return list.find(t => t.id === sort)?.label ?? '帖子列表';
 }
 
-export default function FeedSortBar({ value, onChange, postTotal, pendingValue }: Props) {
+export default function FeedSortBar({
+  value,
+  onChange,
+  postTotal,
+  pendingValue,
+}: Props) {
   const { limits } = useForumLimits();
   const options = useMemo(
     () => enabledFeedSortTabs(limits.feed_sort_tabs).map(t => ({