Python: Document ChatKit frontend requirements and air-gapped limitations (#2587)

- Add "Requirements and Limitations" section to chatkit package README
- Add "Network Requirements" and "Limitations" sections to chatkit-integration sample README
- Add explanatory comments in frontend code for CDN dependency and domain key configuration

Fixes #2347

python/samples/demos/chatkit-integration/frontend/index.html

@@ -4,6 +4,11 @@
     <meta charset="UTF-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <title>ChatKit + Agent Framework Demo</title>
+    <!--
+      IMPORTANT: The ChatKit UI library is loaded from OpenAI's CDN and cannot be self-hosted.
+      This requires internet connectivity and is not suitable for air-gapped environments.
+      See: https://github.com/openai/chatkit-js/issues/57
+    -->
     <script src="https://cdn.platform.openai.com/deployments/chatkit/chatkit.js"></script>
     <style>
       * {

python/samples/demos/chatkit-integration/frontend/src/App.tsx

@@ -1,6 +1,12 @@
 import { ChatKit, useChatKit } from "@openai/chatkit-react";
 
 const CHATKIT_API_URL = "/chatkit";
+
+// Domain key for ChatKit integration
+// - Local development: Uses default "domain_pk_localhost_dev"
+// - Production: Register your domain at https://platform.openai.com/settings/organization/security/domain-allowlist
+//   and set VITE_CHATKIT_API_DOMAIN_KEY in your .env file
+// See: https://github.com/openai/chatkit-js/issues/76
 const CHATKIT_API_DOMAIN_KEY =
   import.meta.env.VITE_CHATKIT_API_DOMAIN_KEY ?? "domain_pk_localhost_dev";