fix(container): preserve file permissions in SGLang dev venv setup (#8408)

Signed-off-by: Krishnan Prashanth <kprashanth@nvidia.com>

container/templates/dev.Dockerfile

@@ -299,8 +299,9 @@ COPY --from=wheel_builder --chown=dynamo:0 --chmod=775 /workspace/.venv/bin/matu
 COPY --from=ghcr.io/astral-sh/uv:0.10.7 /uv /tmp/uv-binary
 RUN mkdir -p /opt/dynamo/venv && \
     python3 -m venv --system-site-packages /opt/dynamo/venv && \
-    cp -r --no-preserve=mode /usr/local/lib/python${PYTHON_VERSION}/dist-packages/* \
+    cp -r /usr/local/lib/python${PYTHON_VERSION}/dist-packages/* \
           /opt/dynamo/venv/lib/python${PYTHON_VERSION}/site-packages/ && \
+    chmod -R g+w /opt/dynamo/venv/lib/python${PYTHON_VERSION}/site-packages/ && \
     cp /tmp/uv-binary /opt/dynamo/venv/bin/uv && \
     chmod +x /opt/dynamo/venv/bin/uv && \
     pip install --ignore-installed maturin[patchelf]