Show HN: AI support chatbot with RAG and citations – one back end file, no infra

Upload markdown docs, get a support chatbot that answers with citations. The entire backend is one JS file — storage, search, and conversation history are handled by the runtime. Stack: Next.js + OnCell + OpenRouter. Demo: https://youtu.be/rWIU43pOH5Y https://youtu.be/rWIU43pOH5Y