Replace deprecated cudarc memcpy_stod with clone_htod across all GPU
upload paths (14 call sites in trainers, cuda_pipeline, hyperopt).
Replace deprecated memcpy_dtov with clone_dtoh in ml-supervised
gpu_tensor.rs.
Bridge GpuTensor-migrated submodules (xLSTM, Liquid CfC, TFT GRN)
with Candle Tensor callers via from_candle_tensor/to_candle_tensor
conversion utilities at API boundaries. Fix CudaDevice->CudaContext
in ml-dqn distributional_dueling.rs.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>