feat: Add going to production docs

src/app/api/[..._path]/route.ts

@@ -0,0 +1,11 @@
+import { initApiPassthrough } from "langgraph-nextjs-api-passthrough";
+
+// This file acts as a proxy for requests to your LangGraph server.
+// Read the [Going to Production](https://github.com/langchain-ai/agent-chat-ui?tab=readme-ov-file#going-to-production) section for more information.
+
+export const { GET, POST, PUT, PATCH, DELETE, OPTIONS, runtime } =
+  initApiPassthrough({
+    apiUrl: process.env.LANGGRAPH_API_URL, // default, if not defined it will attempt to read process.env.LANGGRAPH_API_URL
+    apiKey: process.env.LANGSMITH_API_KEY, // default, if not defined it will attempt to read process.env.LANGSMITH_API_KEY
+    runtime: "edge", // default
+  });