Build faliure fix 2

Fixed the new build failure in [src/proxy.ts]

src/proxy.ts

@@ -82,7 +82,9 @@ function buildCsp(): string {
   ].join("; ");
 }
 
-export async function handleProxyRequest(req: NextRequest) {
+type AuthenticatedNextRequest = NextRequest & { auth?: unknown };
+
+export async function handleProxyRequest(req: AuthenticatedNextRequest) {
   const { pathname } = req.nextUrl;
   const csp = buildCsp();