Catholic Primaries for Sabbath-Sunday Debate

Ongoing effort to collect and organize Catholic doctrinal sources (CCC 2168-2195, Sacrosanctum Concilium, Laetare, patristic citations) for use in SDA apologetics. Partial progress; still need full extracts and verification against devotional noise. Added a short historical snippet on Sunday laws (Constantine to colonial Virginia) in previous batch. This batch added a Catholic article on the five precepts (Sunday Mass obligation) as a primary source.