Frozen evaluation samples

strict_test_fold3_samples.json: the 3,000 frozen samples (300 per gap length L=1-10) of the strict protocol -- whole inscriptions, real lacunae in context, spaces counted, PHI identifiers ending in 3 (Ithaca's own test split). Every system in the paper's strict table reads exactly this file, so strict-table numbers reproduce exactly from it. Text derives from the PHI corpus via the normalization in data/normalize.py.