Data: nightly parity reference archive (reference-data-v2)

Reference-engine outputs for bngsim's nightly parity check (issue #805), recorded by https://github.com/lanl/bngsim/actions/runs/40404704911 at 104078d.

Not a bngsim release. One asset per suite; each holds a README, entries.json (every entry's model, source and license) and, where any entry is not CC0, bngsim's NOTICE. The nightly replays from these once parity_checks/nightly/reference_archive.json pins them; parity_checks/nightly/README.md has the procedure.