Decimal 196 finite-orbit audit

This artifact pins three bounded experiments to explicit windows and estimators. It does not assert anything about the orbit after step 4,000.

Run:

python3 check_196_orbit.py --output certificate.json
python3 verify_196_orbit.py certificate.json

check_196_orbit.py uses Python integers and decimal strings. verify_196_orbit.py independently implements reverse-and-add as digit-list addition and requires exact agreement with every certificate field.

The carry statistic uses the incoming carry at each least-significant-first column, including the initial zero carry. Subword sets never cross a boundary between two orbit states. Shifted reflection distance is the mean of the per-state normalized distances over valid index pairs.