docs(cff): add Citation File Format v1.2.0 block for DOI 10.5281/zenodo.20018487

Point YAML configs at Parquet files for Viewer

Add Parquet for default (Dataset Viewer activation)

docs: add Zenodo DOI 10.5281/zenodo.20018487 citation block

Enrich dataset card YAML + Wikidata sameAs + BibTeX citation

add metadata.json

add data/source_index.json

add data/sections.jsonl

add README.md

initial commit