OpenAI API-compliant endpoint that proxies requests and adds context automatically

[ianmacartney]

Pass up the threadID and authenticate on the endpoint (or generate JWT from the component?) - so you can send simple requests up that get augmented with history automatically, for driving from the client - can also add the OPENAI_API_KEY to the forwarded header

also:

• issue one-off tokens so clients can call via the proxy, with per-user rate limiting and usage tracking
• maybe the one-off token is the threadId?