CLAUDE: initial import — DNN training/eval/export (migrated from imagej-elphel-internal/c5p_dnn)

L1 RawFCN + L2 ConvGRU(torus), synthetic data gen, training/eval, infer_server,
and export_torchscript.py (self-contained TorchScript for native LibTorch inference).
GPLv3 (Elphel norm); headers on all .py/.sh; LICENSE = GPLv3. runs/ checkpoints untracked.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>