heliosdb-nano-graph-rag

Knowledge-graph + RAG pipeline in HeliosDB-Nano. Adds the _hdb_graph_* universal schema on top of code-graph, plus seed/expand/rerank traversal and domain-specific ingestors for documents (PDF, Office, Markdown), audio (transcribed), images (captioned), email, issues, and Q&A. Pair with HNSW vector search (heliosdb-nano-vector) for hybrid retrieval. Use this when the user wants a full RAG stack — indexing…