raggity v0.5.0

Lightweight GraphRAG (opt-in, raggity[graph]): set retrieval.graph=true and rag ingest (or rag graph-build) extracts entities+relations per chunk via your LLM into a networkx knowledge graph; at query time the question's entities are linked and their graph neighborhood is merged into retrieval before reranking — better multi-hop/connect-the-dots answers. Not Microsoft-style community summarization; off by default (zero cost unless enabled).