fix: Add Next.js middleware to enforce trailing slash for framework-docs

Author: GeneAI

website/middleware.ts

@@ -0,0 +1,21 @@
+import { NextResponse } from 'next/server';
+import type { NextRequest } from 'next/server';
+
+export function middleware(request: NextRequest) {
+  const pathname = request.nextUrl.pathname;
+
+  // Add trailing slash to framework-docs paths (except for files with extensions)
+  if (pathname.startsWith('/framework-docs/') &&
+      !pathname.endsWith('/') &&
+      !pathname.match(/\.[a-zA-Z0-9]+$/)) {
+    const url = request.nextUrl.clone();
+    url.pathname = pathname + '/';
+    return NextResponse.redirect(url, 308);
+  }
+
+  return NextResponse.next();
+}
+
+export const config = {
+  matcher: '/framework-docs/:path*',
+};