The upstream deepseek_v4.py has imports that don't exist in the nightly
Docker image (norm_gate_linear, breakable_cudagraph, etc.). Use the
nightly's own files as the base and add only the minimal NVFP4 changes:
- Add _make_deepseek_v4_nvfp4_weights_mapper() for checkpoint key mapping
- Select NVFP4 mapper when quant_config is modelopt_fp4
- cos_sin_cache float32 fix in attention
- Remove utils.py patch (not needed)