fix(redirect+docs): 补 language/papers 精确 index 301 + 删 syncedFromPosts 死代码

Copilot CR（#351）：

- next.config.mjs：language / papers 各补一条无 :path* 的精确 index 规则，
  防止空路径命中 :path* wildcard 产生尾斜杠，避免 301→308 双跳。
- page.tsx：删 syncedFromPosts eyebrow 渲染块（删+301 路线已无 doc 携带该字段）。
- doc.ts：删 PageData 的 syncedFromPosts / syncedAuthor / syncedPostsUrl 字段（死代码）。

Co-authored-by: copilot-pull-request-reviewer[bot] <198982749+copilot-pull-request-reviewer[bot]@users.noreply.github.com>

Author: github-actions[bot]

app/[locale]/docs/[...slug]/page.tsx

@@ -126,17 +126,6 @@ export default async function DocPage({ params }: Param) {
       />
       <DocsPage toc={page.data.toc}>
         <DocsBody>
-          {data.syncedFromPosts && data.syncedPostsUrl && (
-            <p className="font-mono text-[10px] uppercase tracking-widest text-neutral-500 mb-4">
-              此文同步自作者主页 →{" "}
-              <a
-                href={data.syncedPostsUrl}
-                className="underline hover:text-neutral-700 dark:hover:text-neutral-300 transition-colors"
-              >
-                {data.syncedAuthor ? `${data.syncedAuthor} 的文章` : "原文"}
-              </a>
-            </p>
-          )}
           <div className="mb-6 flex flex-col gap-3 border-b border-border pb-6 md:mb-8 md:flex-row md:items-start md:justify-between">
             <h1 className="text-3xl font-extrabold tracking-tight md:text-4xl">
               {page.data.title}

app/types/doc.ts

@@ -39,11 +39,6 @@ export interface PageData {
     lang?: string;
     [key: string]: unknown;
   };
-  // docs 文章同步自作者 posts 主页时在 frontmatter 设置，
-  // 渲染层据此在文章顶部加「此文同步自作者主页 →」导航提示。
-  syncedFromPosts?: boolean;
-  syncedAuthor?: string;
-  syncedPostsUrl?: string;
   // 故意不挂顶层 [key: string]: unknown 索引签名 —— Fumadocs 的 page.data 由
   // zod DocOut 推出，没有 index signature；如果在 PageData 上挂一个，as PageData
   // 会触发 TS2352 "neither type sufficiently overlaps"。所有需要的字段都已

next.config.mjs

@@ -227,13 +227,23 @@ const config = {
         destination: "/zh/docs/learn/cs/dev-tips/:path*",
         statusCode: 301,
       },
-      // language（语言考试）→ career/language
+      // language（语言考试）→ career/language；精确 index + wildcard 各一条，防空路径双跳
+      {
+        source: "/docs/community/language",
+        destination: "/zh/docs/career/language",
+        statusCode: 301,
+      },
       {
         source: "/docs/community/language/:path*",
         destination: "/zh/docs/career/language/:path*",
         statusCode: 301,
       },
-      // papers（AI 论文读书笔记）→ learn/ai/papers
+      // papers（AI 论文读书笔记）→ learn/ai/papers；同上
+      {
+        source: "/docs/community/papers",
+        destination: "/zh/docs/learn/ai/papers",
+        statusCode: 301,
+      },
       {
         source: "/docs/community/papers/:path*",
         destination: "/zh/docs/learn/ai/papers/:path*",