Add nvidia-modelopt to mcore extra dependencies

megatron-bridge unconditionally imports modelopt at module load time
(auto_bridge.py imports is_quantized). The old MLM workspace's setup.py
bundled nvidia-modelopt as a direct dependency; with that workspace
removed, modelopt is no longer available under --extra mcore.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Kajal Jain <kajalj@nvidia.com>

Author: kajalj22

pyproject.toml

@@ -123,6 +123,7 @@ mcore = [
   "transformer-engine[pytorch,core_cu13] @ git+https://github.com/NVIDIA/TransformerEngine.git@v2.14.1",
   "megatron-core",
   "megatron-bridge",
+  "nvidia-modelopt[torch]; sys_platform != 'darwin'",
   "onnxscript",
   # Flash-attn version should be selected to satisfy both TE + vLLM requirements (xformers in particular)
   # https://github.com/NVIDIA/TransformerEngine/blob/v2.3/transformer_engine/pytorch/attention/dot_product_attention/utils.py#L108