refactor(docker): rebase benchmark images on nightly lerobot-gpu

Use huggingface/lerobot-gpu:latest as base for both libero and metaworld
benchmark Dockerfiles instead of building from nvidia/cuda scratch. The
nightly image already has all extras installed via uv sync --extra all,
so we only need to overlay the PR source code (and libero asset setup).

This eliminates duplicated system dep installation, Python setup, uv
venv creation, and the Triton ptxas workaround from both files.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docker/Dockerfile.benchmark.metaworld

@@ -12,71 +12,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# Isolated benchmark image for MetaWorld integration tests.
-# Installs only lerobot[metaworld] so its dep tree (metaworld==3.0.0, mujoco>=3)
-# cannot conflict with other benchmarks.
+# Benchmark image for MetaWorld integration tests.
+# Extends the nightly GPU image (which already has all extras installed)
+# with the PR's source code.
 #
 # Build:  docker build -f docker/Dockerfile.benchmark.metaworld -t lerobot-benchmark-metaworld .
 # Run:    docker run --gpus all --rm lerobot-benchmark-metaworld lerobot-eval ...
 
-ARG CUDA_VERSION=12.4.1
-ARG OS_VERSION=22.04
-FROM nvidia/cuda:${CUDA_VERSION}-base-ubuntu${OS_VERSION}
+FROM huggingface/lerobot-gpu:latest
 
-ARG PYTHON_VERSION=3.12
-
-ENV DEBIAN_FRONTEND=noninteractive \
-    MUJOCO_GL=egl \
-    PATH=/lerobot/.venv/bin:$PATH \
-    CUDA_VISIBLE_DEVICES=0 \
-    DEVICE=cuda
-
-# System deps — same set as Dockerfile.internal
-RUN apt-get update && apt-get install -y --no-install-recommends \
-    software-properties-common build-essential git curl \
-    libglib2.0-0 libgl1-mesa-glx libegl1-mesa ffmpeg \
-    libusb-1.0-0-dev speech-dispatcher libgeos-dev portaudio19-dev \
-    cmake pkg-config ninja-build \
-    && add-apt-repository -y ppa:deadsnakes/ppa \
-    && apt-get update \
-    && apt-get install -y --no-install-recommends \
-       python${PYTHON_VERSION} \
-       python${PYTHON_VERSION}-venv \
-       python${PYTHON_VERSION}-dev \
-    && curl -LsSf https://astral.sh/uv/0.8.0/install.sh | sh \
-    && mv /root/.local/bin/uv /usr/local/bin/uv \
-    && useradd --create-home --shell /bin/bash user_lerobot \
-    && usermod -aG sudo user_lerobot \
-    && apt-get clean && rm -rf /var/lib/apt/lists/*
-
-WORKDIR /lerobot
-RUN chown -R user_lerobot:user_lerobot /lerobot
-USER user_lerobot
-
-ENV HOME=/home/user_lerobot \
-    HF_HOME=/home/user_lerobot/.cache/huggingface \
-    HF_LEROBOT_HOME=/home/user_lerobot/.cache/huggingface/lerobot \
-    TORCH_HOME=/home/user_lerobot/.cache/torch \
-    TRITON_CACHE_DIR=/home/user_lerobot/.cache/triton
-
-RUN uv venv --python python${PYTHON_VERSION}
-
-# ── Dependency layer (cached unless pyproject.toml / uv.lock change) ────────
-# Copy only the files uv needs to resolve deps, plus a minimal package stub
-# so the editable install can succeed without the full source tree.
-# Uses `uv pip install` instead of `uv sync` — see Dockerfile.benchmark.libero
-# for rationale (cross-extra numpy conflict with robomme).
-COPY --chown=user_lerobot:user_lerobot setup.py pyproject.toml uv.lock README.md MANIFEST.in ./
-RUN mkdir -p src/lerobot && touch src/lerobot/__init__.py src/lerobot/py.typed
-
-RUN uv pip install --no-cache -e ".[metaworld,smolvla]"
-
-# Workaround: Triton ships ptxas without the execute bit set.
-# Without this chmod, any JIT compilation (e.g. torch.compile) fails
-# with "Permission denied". See: https://github.com/triton-lang/triton/issues/2due
-RUN chmod +x /lerobot/.venv/lib/python${PYTHON_VERSION}/site-packages/triton/backends/nvidia/bin/ptxas
-
-# ── Source layer (rebuilds in seconds on code-only changes) ─────────────────
+# Overlay the PR's source code on top of the nightly image.
 COPY --chown=user_lerobot:user_lerobot . .
 
 CMD ["/bin/bash"]