fix: revert proxy back to middleware for Next.js build compatibility

src/middleware.ts

@@ -0,0 +1,35 @@
+import { NextResponse } from "next/server";
+import type { NextRequest } from "next/server";
+
+export function middleware(request: NextRequest) {
+  const response = NextResponse.next();
+
+  const url = request.nextUrl.pathname;
+
+  if (
+    url.startsWith("/sr") ||
+    url.startsWith("/en") ||
+    url.startsWith("/de") ||
+    url.startsWith("/fr") ||
+    url === "/"
+  ) {
+    if (
+      !url.includes("/checkout") &&
+      !url.includes("/cart") &&
+      !url.includes("/api/")
+    ) {
+      response.headers.set(
+        "Cache-Control",
+        "public, max-age=3600, stale-while-revalidate=86400"
+      );
+    }
+  }
+
+  return response;
+}
+
+export const config = {
+  matcher: [
+    "/((?!_next/static|_next/image|favicon.ico|icon.png|robots.txt|sitemap.xml).*)",
+  ],
+};