feat(example): update react-router example to test multimodal attachments

Author: AlemTuzlak

examples/v2/react-router/app/routes/_index.tsx

@@ -5,7 +5,10 @@ export default function Index() {
   return (
     <CopilotKitProvider runtimeUrl="/api/copilotkit" showDevConsole="auto">
       <div className="h-screen w-screen">
-        <CopilotChat className="h-full w-full" />
+        <CopilotChat
+          className="h-full w-full"
+          attachments={{ enabled: true }}
+        />
       </div>
     </CopilotKitProvider>
   );

examples/v2/react-router/app/server.ts

@@ -4,21 +4,14 @@ import {
   createCopilotEndpoint,
   InMemoryAgentRunner,
 } from "@copilotkit/runtime/v2";
-import { chat } from "@tanstack/ai";
-import { openaiText } from "@tanstack/ai-openai";
-import { TanStackAIAgent } from "./agent";
+import { BuiltInAgent } from "@copilotkit/runtime/v2";
 
 export default await createHonoServer({
   configure(app) {
-    const agent = new TanStackAIAgent(
-      ({ messages, systemPrompts, abortController }) =>
-        chat({
-          adapter: openaiText("gpt-4o"),
-          messages,
-          systemPrompts,
-          abortController,
-        }),
-    );
+    const agent = new BuiltInAgent({
+      model: "openai/gpt-4o",
+      prompt: "You are a helpful assistant. When the user sends images or files, describe what you see or analyze the content.",
+    });
 
     const runtime = new CopilotRuntime({
       agents: { default: agent },