Prime: real content (psalms, Martyrology, Regula) and ordo corrections

Pulls in verified content from Divinum Officium rather than placeholders:
17 psalms (2, 6, 7-19, 118, 129), 365 days of the Martyrology, and the full
121-reading Regula cycle, plus the Athanasian Creed.

Ordo corrections driven by review against the real engine output:
- Capitulum and Preces now pick a Sunday/feast vs. ferial form
  (calendar/isSundayOrFeast); ferial Preces said every ferial day by choice.
- Chapter responsory, hymn doxology, and the opening versicle's
  Alleluia/Laus tibi all vary by season via a shared resolver
  (hours/seasonal-propers.ts).
- Real Roman Kalends/Nones/Ides Latin dating (calendar/roman-date.ts,
  verified against 363/365 real Martyrology headings) plus the historical
  "bis sextus" Feb 29 handling, and the Martyrology's Luna (moon-day)
  heading (a ported Golden-Number calculation).
- Fixed responsory structure (was missing its initial full repeat),
  weekday psalm antiphons (opening as incipit-or-full by rank, full
  repeat after the psalms/Creed as its own part, "*" chant mark kept),
  scripture citations on the capitulum/lectio brevis, and V./R. markers
  switched from Unicode symbols to plain text for reliable font rendering.
- Dropped Pretiosa and the dead-commemoration psalm (129) for time;
  trimmed section headings down to the ones that are actually named
  things (Preces, Chapter Office, etc. no longer relabel connective text).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/calendar/index.ts

@@ -20,4 +20,16 @@ export function resolveDay(isoDate: string): LiturgicalDay {
   };
 }
 
+/**
+ * The Sunday/feast-vs-ferial split that several hours' propers key off of
+ * (Prime's capitulum and Preces, so far): a plain weekday with nothing else
+ * going on gets the "ferial" form, Sunday or an occurring feast gets the
+ * fuller "Sunday/feast" form. `occurring` is always [] until milestone 4, so
+ * today this reduces to "is it Sunday" — but the feast-override branch is
+ * real, not a stub, and will start firing the moment feasts do.
+ */
+export function isSundayOrFeast(day: LiturgicalDay): boolean {
+  return day.weekday === 'sunday' || day.occurring.length > 0;
+}
+
 export type { LiturgicalDay, OccurringFeast, Season, Weekday, FeastRank } from './types';