fix(intl): safeguard against missing translation keys and resolve middleware naming conflict

middleware.ts

@@ -0,0 +1,18 @@
+import createMiddleware from "next-intl/middleware";
+
+export default createMiddleware({
+  // A list of all locales that are supported
+  locales: ["de"],
+
+  // Used when no locale matches
+  defaultLocale: "de",
+
+  // Use default locale without prefix
+  localePrefix: "as-needed",
+});
+
+export const config = {
+  // Matcher for all pages and internationalized pathnames
+  // excluding api, _next, static files, etc.
+  matcher: ["/((?!api|_next|.*\\..*).*)"],
+};