Dedupe Matins nocturn readings pooled from two ids on the same day

post-pentecost-15 and month-week-092 land on the same Sunday
(2026-09-06) and independently reuse the identical Gregory the Great
Moralia in Job excerpt -- a real duplication in the reference engine's
own Tempora files, not a vu authoring error. buildReadingPool pooled
both ids and rendered the reading twice; now dedupes by text.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MKC2QQGLYo2UTiDjDyWEkW

src/hours/matins.ts

@@ -839,11 +839,23 @@ function buildReadingPool(day: LiturgicalDay, temporalId: string, date: string,
   // must be handled, not just the usual Sunday/feast pair.
   const ids = nocturnReadingIds(day, temporalId, date, threeNocturns);
   const byNocturn = new Map<number, ResolvedPart[]>();
+  // The reference engine's own Tempora files sometimes independently reuse
+  // the exact same excerpt across two different Sunday-numbering schemes
+  // (e.g. a Pentecost-numbered Sunday and a calendar-month Sunday landing on
+  // the same date — see month-week-092.yml's own header) — only one of
+  // those numbering schemes is ever in force on a given real calendar, but
+  // `nocturnReadingIds` can legitimately pool both ids for the *same* day
+  // here, which would otherwise surface the identical reading twice in one
+  // hour. Dedupe by Latin text, keeping the first (earliest-id) occurrence.
+  const seenReadingText = new Set<string>();
   for (const id of ids) {
     const readings = getNocturnReadings(id);
     let commonPoolIndex = 0;
     for (let i = 0; i < readings.length; i++) {
       const reading = readings[i]!;
+      const textKey = reading.text.la ?? reading.text.en ?? '';
+      if (textKey && seenReadingText.has(textKey)) continue;
+      if (textKey) seenReadingText.add(textKey);
       const bucket = byNocturn.get(reading.nocturn) ?? [];
       if (reading.isGospel) {
         // A genuine separate homily on this pericope is the very next