[francois-drielsma]

Summary

• organize the existing development image as docker/Dockerfile.full
• add an opt-in Ubuntu 24.04 / ROOT 6.34 runtime image containing LArCV core, Python, NumPy, and the required ROOT/Cling runtime
• omit OpenCV, HDF5, Torch, CMake, Git, and optional LArCV applications from the runtime flavor
• test both image flavors in CI, including a runtime ROOT-file round trip and NumPy bridge smoke test
• publish runtime branch/release tags alongside the existing full-image tags while keeping latest on the full image

Runtime tags

• branch: develop-runtime-ubuntu24.04
• release: 2.4.2-runtime-ubuntu24.04
• stable moving alias: runtime

Validation

• local runtime build succeeded on the Ubuntu 24.04 / ROOT 6.34 base
• ROOT/LArCV sparse-3D write/read round trip and NumPy bridge passed
• local image size: 328 MB (docker image ls), approximately 325 MB as a compressed Docker export
• workflow YAML parses successfully and git diff --check passes

The runtime remains opt-in and does not replace the existing latest image.