CORS Policy preventing LLM queries to Azure OpenAI

I was trying to run the example queries on the /play page, and ran into CORS issues with all my requests. I've pasted the chrome dev console logs below, but this is broadly what I expect: CORS should prevent the page from making a javascript request to an OpenAI endpoint, right?

Tools like these usually work around CORS by proxying the requests via a non-CORS-violating backend, but it looks like that's not happening here. Am I misunderstanding CORS / doing something strange here. How could this ever have worked?

> Querying Azure OpenAI deployed model 'gpt-35-turbo' at endpoint 'https://api.llm.palantir.tech/preview' with prompt 'What is the opening sentence of The Poppy War by R.F.Kuang?'...

```
Access to fetch at 'https://api.llm.palantir.tech/preview/openai/deployments/gpt-35-turbo/chat/completions?api-version=2023-03-15-preview' from origin 'https://chainforge.ai' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.
```

Start by reproducing the request from the /play page and inspect the browser's preflight request to the Azure OpenAI endpoint shown in the report. Trace whether the request is intended to use a backend proxy; done means the example query can reach the deployed model without the reported CORS failure.

Written by the indexing model from the issue text.