Test code used CudaDevice (cudarc 0.17) instead of CudaContext (0.19), and wrapped Arc::new(CudaContext::new().new_stream()) which double-wraps since new_stream() already returns Arc<CudaStream>. 740 tests pass across ml-core, ml-ppo, ml-supervised, ml-ensemble. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>