chore: 去掉未上线前的旧兼容垫片，板块流收口到首页

鉴权只认 cookie、SEO 只走 Next、sort 与推荐对齐；删除 Bearer、Go sitemap、post_type 回填等冗余路径。

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

frontend/app/post/[id]/page.tsx

@@ -121,7 +121,7 @@ function BoardCard({ board }: { board: Board }) {
       <p className="j13-module-title mb-3" id="board-card-title">
         <Layers size={15} style={{ color: "var(--accent)" }} /> 所属板块
       </p>
-      <Link href={`/board/${board.id}`} className="flex items-center gap-3 group">
+      <Link href={`/?board=${board.id}`} className="flex items-center gap-3 group">
         <span
           className={`av-${colorIdx} w-11 h-11 rounded-xl flex items-center justify-center text-lg font-extrabold shrink-0`}
         >
@@ -140,10 +140,10 @@ function BoardCard({ board }: { board: Board }) {
         </p>
       )}
       <Link
-        href={`/board/${board.id}`}
+        href={`/?board=${board.id}`}
         className="btn btn-line btn-sm w-full justify-center mt-3.5"
       >
-        进入板块 <ArrowRight size={13} />
+        查看该板讨论 <ArrowRight size={13} />
       </Link>
     </section>
   );
@@ -266,7 +266,7 @@ function RelatedPosts({
         ))}
       </ol>
       <Link
-        href={`/board/${boardId}`}
+        href={`/?board=${boardId}`}
         className="j13-raillink justify-center mt-1.5 text-[12.5px]"
         style={{ color: "var(--accent)" }}
       >
@@ -334,7 +334,7 @@ export default async function PostDetailPage({ params, searchParams }: PageProps
     fetchComments(id, commentPage, cookie),
     getMeCached(cookie || undefined),
     fetchUserProfile(String(post.user.id), 1, cookie).catch(() => null),
-    fetchPosts(1, 8, post.board_id, "hot", "", false, cookie).catch(() => null),
+    fetchPosts(1, 8, post.board_id, "recommended", "", false, cookie).catch(() => null),
   ]);
   const comments = commentsData.comments;
   const related = (relatedData?.posts ?? []).filter((p) => p.id !== post.id).slice(0, 5);
@@ -424,7 +424,7 @@ export default async function PostDetailPage({ params, searchParams }: PageProps
             <nav className="meta mb-5 flex items-center gap-1.5 flex-wrap text-[13px]">
               <Link href="/" className="hover:text-[var(--accent)] transition-colors">首页</Link>
               <ChevronRight size={13} />
-              <Link href={`/board/${post.board.id}`} className="hover:text-[var(--accent)] transition-colors">
+              <Link href={`/?board=${post.board.id}`} className="hover:text-[var(--accent)] transition-colors">
                 {post.board.name}
               </Link>
             </nav>
@@ -432,7 +432,7 @@ export default async function PostDetailPage({ params, searchParams }: PageProps
             <div className="panel p-6 sm:p-8">
               <header className="mb-7">
                 <div className="flex items-center gap-2 mb-4 flex-wrap">
-                  <Link href={`/board/${post.board.id}`} className="chip">
+                  <Link href={`/?board=${post.board.id}`} className="chip">
                     {post.board.name}
                   </Link>
                 </div>