add minimal Docker image (no CUDA, no Jupyter, batch-only Geant4)

Dockerfile-mini builds a lightweight image with only what's needed to
run the bind/ examples: Geant4 v11.1.2 (batch mode, no visualization),
Python 3.10, and numpy/pandas/uproot/awkward/plotly/ipython.
Examples are copied to /examples which is also the working directory.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker/Dockerfile-mini

@@ -0,0 +1,67 @@
+FROM ubuntu:22.04
+
+SHELL ["/bin/bash", "-c"]
+
+USER root
+ENV DEBIAN_FRONTEND=noninteractive
+
+# Build tools + minimal Python
+RUN apt-get update -y && apt-get install -y \
+    python3 python3-dev python3-pip \
+    cmake g++ gcc binutils \
+    libssl-dev wget git \
+    && rm -rf /var/lib/apt/lists/*
+
+RUN python3 -m pip install --upgrade pip && \
+    python3 -m pip install numpy pandas uproot awkward plotly ipython && \
+    ln -sf /usr/bin/python3 /usr/bin/python
+
+# Geant4 v11.1.2 — batch mode only (no visualization, no multithreading)
+RUN wget -q https://gitlab.cern.ch/geant4/geant4/-/archive/v11.1.2/geant4-v11.1.2.tar.gz && \
+    tar -xzf geant4-v11.1.2.tar.gz -C /tmp && \
+    rm geant4-v11.1.2.tar.gz && \
+    mkdir /tmp/geant4-v11.1.2-build && \
+    cmake \
+        -S /tmp/geant4-v11.1.2 \
+        -B /tmp/geant4-v11.1.2-build \
+        -DCMAKE_INSTALL_PREFIX=/opt/geant4-v11.1.2 \
+        -DCMAKE_RULE_MESSAGES=OFF \
+        -DGEANT4_INSTALL_DATA=ON \
+        -DGEANT4_BUILD_MULTITHREADED=OFF \
+        -DGEANT4_BUILD_TLS_MODEL=global-dynamic \
+        > /dev/null && \
+    cmake --build /tmp/geant4-v11.1.2-build --parallel $(nproc) > /dev/null && \
+    cmake --install /tmp/geant4-v11.1.2-build > /dev/null && \
+    rm -rf /tmp/geant4-v11.1.2 /tmp/geant4-v11.1.2-build
+
+ENV LD_LIBRARY_PATH="/opt/geant4-v11.1.2/lib:${LD_LIBRARY_PATH}"
+
+# Build minicalo
+ARG BUILD_DATE
+ARG COMMIT
+ARG USER
+LABEL org.label-schema.build-date=$BUILD_DATE
+
+ADD minicalosim /root/minicalosim
+
+RUN cd /root/minicalosim && git checkout $COMMIT && \
+    git submodule update --init && \
+    cmake \
+        -S . -B build \
+        -DWITH_GEANT4_UIVIS=OFF \
+        > /dev/null && \
+    cmake --build build --parallel $(nproc) && \
+    cp build/minicalo*.so /usr/local/lib/python3.10/dist-packages/
+
+RUN cp /root/minicalosim/bind/G4Calo.py \
+       /root/minicalosim/bind/minicalo_tools.py \
+       /root/minicalosim/bind/minipandas.py \
+       /usr/local/lib/python3.10/dist-packages/ && \
+    install -m 755 /root/minicalosim/bind/G4Calo_exec.py /usr/local/bin/G4Calo_exec.py
+
+# Copy examples
+RUN cp -r /root/minicalosim/bind /examples && \
+    rm -rf /root/minicalosim
+
+WORKDIR /examples
+CMD ["bash"]