Most RAG tutorials explain the concept. This one shows the code — a complete working pipeline using LangChain, ChromaDB, and a local LLM via LM Studio. No OpenAI API key. No cloud costs. The business problem: A company has hundreds of pages of HR documentation. Employees ask questions. An AI answers accurately from the actual documents in seconds. Stack: Python, LangChain, ChromaDB, nomic-embed-text, Qwen 9B via LM Studio pip install langchain langchain-community langchain-ch...