TL;DR

Added a new chat API to stream LLM responses from Pair based on user inputs.

What changed?

• Created a new /api/chat endpoint that handles streaming chat responses
• Added Langfuse integration for prompt management and observability
• Set up feature flag integration with Launch Darkly for prompt configuration

How to test?

1. Send a POST request to /api/chat with a valid authentication token
2. Include a request body with the following structure:

   {
     "messages": [
       {
         "role": "user",
         "parts": [{ "type": "text", "text": "Your message here" }]
       }
     ],
     "userId": "optional-user-id",
     "sessionId": "optional-session-id"
   }

3. Verify that the response is streamed back