Add Python and R containers with reproducibility CI

[rickyjreyes]

Summary

• adds a canonical CPU Python image
• adds a separate R image with the required GMP system dependency
• runs the Python tests and a reduced Fe II scan in CI
• builds and smoke-tests both container implementations
• retains the committed canonical Python outputs inside the R image so parity tests do not silently skip

Full 5,000-null production analyses remain outside ordinary pull-request CI.