From 923529a132f4aaf3b60d29be2a546b6a0a3c5f88 Mon Sep 17 00:00:00 2001
From: bntvllnt <bntvllnt@users.noreply.github.com>
Date: Thu, 18 Jun 2026 21:47:16 +0200
Subject: [PATCH] fix(registry): redirect /design.md to canonical /DESIGN.md

Lowercase /design.md returned 404 while /DESIGN.md (referenced in
sitemap.ts, llms.txt and llms-full.txt) served the design guide. Add a
308 redirect so the natural lowercase guess resolves to the canonical
markdown route.

Done in middleware, not a route folder or next.config: a sibling
app/design.md/route.ts is rejected by tsc (folder casing collision with
DESIGN.md), and next.config redirects() match case-insensitively, which
would loop /DESIGN.md -> /DESIGN.md. A case-sensitive check in middleware
avoids both while leaving the canonical route untouched.

Closes #447

Claude-Session: https://claude.ai/code/session_01Kx4Zwv76SZhVxwctKsquBN
---
 apps/registry/middleware.ts | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/apps/registry/middleware.ts b/apps/registry/middleware.ts
index 75185a78..5fd427cc 100644
--- a/apps/registry/middleware.ts
+++ b/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|.*\\.[^/]+$).*)",
   ],
 };