Function getIndex

Server-only entry point for the chart-review code ported from circlehealthai-web. Importing this module pulls in @langchain/*, @pinecone-database/pinecone, and openai, so it must never be reached from a client bundle.

This is the bootstrap surface — primitives only. The orchestrators (runChartReview, runChartReviewSingleQuestion) land in later PRs.