fix(registry): redirect /design.md to canonical /DESIGN.md

apps/registry/middleware.ts

@@ -1,11 +1,33 @@
+import { type NextRequest, NextResponse } from "next/server";
 import createMiddleware from "next-intl/middleware";
 
 import { routing } from "@/i18n/routing";
 
-export default createMiddleware(routing);
+const intlMiddleware = createMiddleware(routing);
+
+export default function middleware(request: NextRequest): NextResponse {
+  const { pathname } = request.nextUrl;
+
+  // Case-sensitive redirect for the lowercase guess of the design guide.
+  // Can't use a route folder (tsc rejects design.md colliding with DESIGN.md)
+  // nor next.config redirects() (matches case-insensitively -> loops /DESIGN.md).
+  if (pathname === "/design.md") {
+    const target = request.nextUrl.clone();
+    target.pathname = "/DESIGN.md";
+
+    return NextResponse.redirect(target, 308);
+  }
+
+  if (pathname.toLowerCase() === "/design.md") {
+    return NextResponse.next();
+  }
+
+  return intlMiddleware(request);
+}
 
 export const config = {
   matcher: [
+    "/design.md",
     "/((?!api|_next|_vercel|mcp|embed|r/|atom\\.xml|rss\\.xml|design\\.txt|llms\\.txt|llms-full\\.txt|sitemap\\.xml|robots\\.txt|manifest\\.webmanifest|.*\\.[^/]+$).*)",
   ],
 };