refactor(frontend): remove featured post component and simplify home page logic

移除了不再使用的FeaturePost组件，同时调整首页帖子展示逻辑：不再单独拆分今日精选帖，将所有非置顶帖子统一纳入普通列表展示，更新了置顶区的注释说明。

frontend/app/page.tsx

@@ -5,7 +5,6 @@ import { PenSquare, SearchX, MessagesSquare, Check, ArrowRight } from "lucide-re
 import { fetchPosts, fetchBoards } from "@/lib/api";
 import Pagination from "@/components/Pagination";
 import PostRow from "@/components/PostRow";
-import FeaturePost from "@/components/FeaturePost";
 import PinnedPosts from "@/components/PinnedPosts";
 
 export const metadata: Metadata = {
@@ -27,12 +26,10 @@ export default async function HomePage({ searchParams }: HomePageProps) {
     fetchBoards(),
   ]);
 
-  // 第一页且非搜索时拆分为三段：管理员置顶 → 今日精选（首条非置顶）→ 普通列表
+  // 第一页且非搜索时：管理员置顶独立成区，其余进入普通列表
   const split = page === 1 && !keyword;
   const pinned = split ? postsData.posts.filter((p) => p.pinned > 0) : [];
-  const normal = split ? postsData.posts.filter((p) => p.pinned <= 0) : postsData.posts;
-  const feature = split && normal.length > 0 ? normal[0] : null;
-  const rows = feature ? normal.slice(1) : normal;
+  const rows = split ? postsData.posts.filter((p) => p.pinned <= 0) : postsData.posts;
 
   return (
     <div>
@@ -63,11 +60,6 @@ export default async function HomePage({ searchParams }: HomePageProps) {
         {/* 主列 */}
         <div>
           <PinnedPosts posts={pinned} />
-          {feature && (
-            <div className="mb-6">
-              <FeaturePost post={feature} />
-            </div>
-          )}
 
           <div className="panel overflow-hidden">
             {rows.length > 0 ? (