feat(policies): add Nvidia Gr00t N1.5 model (#2292)

* feat(policies): add Nvidia Gr00t N1.5 model

Co-authored-by: lbenhorin <lbenhorin@nvidia.com>
Co-authored-by: Aravindh <aravindhs@nvidia.com>
Co-authored-by: nv-sachdevkartik <ksachdev@nvidia.com>
Co-authored-by: youliangt <youliangt@nvidia.com>
Co-authored-by: Michel Aractingi <michel.aractingi@huggingface.co>
Co-authored-by: Pepijn <138571049+pkooij@users.noreply.github.com>
Co-authored-by: Jade Choghari <chogharijade@gmail.com>

* fix(docs): add groot to index

Co-authored-by: sachdevkartik <sachdev.kartik25@gmail.com>

---------

Co-authored-by: lbenhorin <lbenhorin@nvidia.com>
Co-authored-by: Aravindh <aravindhs@nvidia.com>
Co-authored-by: nv-sachdevkartik <ksachdev@nvidia.com>
Co-authored-by: youliangt <youliangt@nvidia.com>
Co-authored-by: Michel Aractingi <michel.aractingi@huggingface.co>
Co-authored-by: Pepijn <138571049+pkooij@users.noreply.github.com>
Co-authored-by: Jade Choghari <chogharijade@gmail.com>
Co-authored-by: sachdevkartik <sachdev.kartik25@gmail.com>

.github/workflows/full_tests.yml

@@ -78,7 +78,7 @@ jobs:
           python-version: ${{ env.PYTHON_VERSION }}
 
       - name: Install lerobot with all extras
-        run: uv sync --all-extras
+        run: uv sync --all-extras --no-extra groot # TODO(Steven): Make flash-attn optional
 
       - name: Run pytest (all extras)
         run: uv run pytest tests -vv --maxfail=10