Add helpers and types for BFF API

lib/api/cmFetch.ts

@@ -0,0 +1,16 @@
+import { RequestInit } from "next/dist/server/web/spec-extension/request";
+
+const FRONTEND_URL = process.env.FRONTEND_URL;
+
+export async function cmFetch<T>(
+  bffUrl: string | URL,
+  options?: RequestInit,
+): Promise<T> {
+  const response = await fetch(`${FRONTEND_URL}/${bffUrl}`, options);
+
+  if (!response.ok) {
+    throw new Error("Request failed");
+  }
+
+  return response.json();
+}