fix(docs-site): add docs index redirect, test, and trim Accept media type

Redirect bare /docs to the introduction page with proper metadata
resolution. Add a test for the redirect. Trim the media type in the
Accept header parser so whitespace around semicolons does not break
markdown content negotiation. Add a test script to package.json.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docs-site/app/docs/[[...slug]]/page.tsx

@@ -5,15 +5,26 @@ import {
   DocsTitle,
   DocsDescription,
 } from "fumadocs-ui/page";
-import { notFound } from "next/navigation";
+import { notFound, redirect } from "next/navigation";
 import defaultMdxComponents from "fumadocs-ui/mdx";
 import { CodeBlock } from "@/components/code-block";
 import { DocsPageActions } from "@/components/docs-page-actions";
 
+const docsIndexPath = "/docs/getting-started/introduction";
+const docsIndexSlug = ["getting-started", "introduction"] as const;
+
+function isDocsIndex(slug: string[] | undefined) {
+  return slug === undefined || slug.length === 0 || slug.join("/") === "";
+}
+
 export default async function Page(props: {
   params: Promise<{ slug?: string[] }>;
 }) {
   const params = await props.params;
+  if (isDocsIndex(params.slug)) {
+    redirect(docsIndexPath);
+  }
+
   const page = source.getPage(params.slug);
   if (!page) notFound();
 
@@ -35,14 +46,16 @@ export default async function Page(props: {
 }
 
 export function generateStaticParams() {
-  return source.generateParams();
+  return [{ slug: [""] }, ...source.generateParams()];
 }
 
 export async function generateMetadata(props: {
   params: Promise<{ slug?: string[] }>;
 }) {
   const params = await props.params;
-  const page = source.getPage(params.slug);
+  const page = source.getPage(
+    isDocsIndex(params.slug) ? [...docsIndexSlug] : params.slug,
+  );
   if (!page) notFound();
 
   return {