AI Integration for Node Vue App

I have a working stack—Node.js on the backend and a Vue-powered front end—and now I need the intelligence layer wired in. The core codebase is solid; what’s missing is the connection to the AI service itself: authenticating against the API, structuring requests, streaming or batching the responses back to the client, and handling edge cases such as rate limits and error recovery. You’ll dive straight into the existing repo, add the necessary service wrappers in Node, expose clean endpoints, and update the Vue components so users see live AI-driven results without page reloads. Clear, well-commented code and concise setup notes are part of the hand-off, so I can extend or swap models later if needed. If you’ve previously integrated OpenAI, Anthropic, or similar REST/GraphQL endpoints in a JavaScript environment, this should feel familiar. Please share a brief note on one integration you’ve shipped, along with the repo or a code snippet that shows your best practice around token handling and streaming responses.