Merge pull request #119 from #118

refactor: _get_column_info 함수 최적화

chore: Update dependencies and environment variable handling

- Bump package version to 0.1.9
- Add python-dotenv and faiss-cpu to dependencies
- Implement .env file loading in chains.py
- Update graph.py to use os.getcwd() for file paths

chore: Update README path and bump package version to 0.1.8