Reorganize repo: data/, pipeline/, scripts/ directories

- data/: estimation output CSVs (archived by Zenodo)
- pipeline/: SAS data build + HDF5 conversion
- scripts/: job submission wrappers (SGE, Slurm) + utilities
- Remove dead files: data.sas (superseded), index.html, README.org

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Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>