Sourced from Divinum Officium's explicit "[Monastic Vespera]" block
(Latin+English Psalmorum), not the ambiguous unlabeled Day/Daya tables
earlier in the same file — confirmed by cross-checking Monday's psalms
against the already live-verified Lauds antiphons, which the unlabeled
tables both got wrong. Only 4 psalms a day (Rule of Benedict ch. 17),
with two real wrinkles: Ps 115+116 joined under one shared antiphon on
Monday, and Ps 138/143 each split across two verse-ranges under one
shared antiphon (Thu/Fri) — modeled by letting a group's `psalms` list
take `{number, verses}` entries alongside plain numbers.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
