sklearn was not installed in the container, causing ModuleNotFoundError on import of ai_tools.py and preventing the server from starting. Replaced with a self-contained numpy k-means++ implementation: - k-means++ seeding for better initial centers - 20-iteration Lloyd's algorithm - Same output: hex colors sorted by cluster frequency No new dependencies required. https://claude.ai/code/session_01B58MaJCU1R6KwBDJCp8AfN