- Implemented `ChromaVectorDBStorage` class in `lightrag/kg/chroma_impl.py` to support ChromaDB as a vector storage backend.
- Updated `lightrag.py` to include `ChromaVectorDBStorage` in the storage class mapping.
- Added a test script `test_chromadb.py` to demonstrate the usage of ChromaDB with LightRAG, including configuration for embedding functions and ChromaDB connection settings.
- fix lazy import function to support package context for dynamic class loading.
288d4b8355
