Annotate plain-Sunday-sourced Matins readings with their occasion

occasionName() only recognized saints, named temporal feasts, and Ember
days, so any reading pooled under a plain governing-Sunday id
(post-pentecost-15, month-week-092, etc.) -- the most common id shape
in the whole pool -- silently got no "(for ...)" annotation. This is
why Sept 6's Gregory the Great homily and its paired Augustine Gospel
homily showed up with no indication of why they were present. Falls
back to the same getDayLabel() the day's own heading already uses.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T6rG4RTNqLFYcyjbCGkPFs

src/hours/matins.ts

@@ -782,24 +782,35 @@ function fallbackHagiographicLabel(id: string): string | undefined {
 }
 
 /** The human-readable occasion a `nocturn-readings` id stands for — a
- * saint's or named temporal feast's own display name, or an Ember day's
- * (which has no `TemporalFeastRecord` of its own, see `emberDayLabel`'s own
- * doc comment). Used to annotate an authored patristic `source` with *why*
- * it's here, since a single day can pool several ids' worth of readings
- * (e.g. a commemorated Ember day's own Gospel homily alongside the winning
- * saint's own) and a bare "Pope St. Gregory the Great, Homily 33" doesn't
- * tell a reader which occasion that homily belongs to. */
-function occasionName(id: string): string | undefined {
-  return getSaintRecord(id)?.name ?? getTemporalFeastRecord(id)?.name ?? emberDayLabel(id)?.en;
+ * saint's or named temporal feast's own display name, an Ember day's (which
+ * has no `TemporalFeastRecord` of its own, see `emberDayLabel`'s own doc
+ * comment), or — the most common case in the whole pool — a plain governing
+ * Sunday's own temporal-cycle id (`post-pentecost-15`) or its
+ * `month-week-<NNN>` half (see `nocturnReadingIds`'s `temporalKept` block),
+ * which falls back to the same `getDayLabel` the day's own heading uses
+ * (e.g. "The 14th Sunday after Trinity"). Used to annotate an authored
+ * patristic `source` with *why* it's here, since a single day can pool
+ * several ids' worth of readings (e.g. a commemorated Ember day's own
+ * Gospel homily alongside the winning saint's own) and a bare "Pope St.
+ * Gregory the Great, Homily 33" doesn't tell a reader which occasion that
+ * homily belongs to. */
+function occasionName(id: string, day: LiturgicalDay): string | undefined {
+  const named = getSaintRecord(id)?.name ?? getTemporalFeastRecord(id)?.name ?? emberDayLabel(id)?.en;
+  if (named) return named;
+  const monthWeek = monthWeekId(day.date);
+  if (id === resolveTemporalId(day.date) || (monthWeek && id === `month-week-${monthWeek}`)) {
+    return getDayLabel(day).en;
+  }
+  return undefined;
 }
 
 /** Appends `(for <occasion>)` to an authored patristic `source` string,
  * when the contributing id resolves to a human-readable occasion name —
  * see `occasionName`. A no-op when `source` is undefined (the hagiographic
  * fallback case, which already names its own saint). */
-function withOccasion(source: string | undefined, id: string): string | undefined {
+function withOccasion(source: string | undefined, id: string, day: LiturgicalDay): string | undefined {
   if (!source) return source;
-  const occasion = occasionName(id);
+  const occasion = occasionName(id, day);
   return occasion ? `${source} (for ${occasion})` : source;
 }
 
@@ -809,12 +820,12 @@ function withOccasion(source: string | undefined, id: string): string | undefine
  * same convention as the per-book pool. Common-category fallback only
  * applies to a real saint id (`getSaintRecord(id)?.common`) — a temporal or
  * octave id has no Commune category to fall back to. */
-function nocturnReadingPart(r: NocturnReading, id: string, index: number): ResolvedPart {
+function nocturnReadingPart(r: NocturnReading, id: string, index: number, day: LiturgicalDay): ResolvedPart {
   const responsoryText = r.responsory ?? getResponsoryForCommon(getSaintRecord(id)?.common, index);
   return {
     kind: 'lesson',
     text: { text: r.text, status: r.status, citation: r.citation },
-    label: withOccasion(r.source, id) ?? fallbackHagiographicLabel(id),
+    label: withOccasion(r.source, id, day) ?? fallbackHagiographicLabel(id),
     responsory: responsoryText ? { text: responsoryText, status: { la: 'verified', en: 'verified' } } : undefined,
   };
 }
@@ -827,7 +838,13 @@ function nocturnReadingPart(r: NocturnReading, id: string, index: number): Resol
  * ResolvedPart can't be split across two nocturns by `distributeIntoNocturns`,
  * whereas two adjacent pool entries could be (and, before this, sometimes
  * were). */
-function gospelReadingPart(r: NocturnReading, homily: NocturnReading | undefined, id: string, index: number): ResolvedPart {
+function gospelReadingPart(
+  r: NocturnReading,
+  homily: NocturnReading | undefined,
+  id: string,
+  index: number,
+  day: LiturgicalDay,
+): ResolvedPart {
   const incipit = getGospelIncipitFromCitation(r.citation);
   // A responsory authored on the *homily* (the reference engine's own
   // convention — e.g. post-pentecost-16.yml's Ambrose homily, or a saint's
@@ -841,11 +858,11 @@ function gospelReadingPart(r: NocturnReading, homily: NocturnReading | undefined
   return {
     kind: 'gospel',
     text: { text: r.text, status: r.status, citation: r.citation },
-    source: withOccasion(r.source, id),
+    source: withOccasion(r.source, id, day),
     label: incipit ? { la: incipit.la, en: incipit.en } : undefined,
     responsory: responsoryText ? { text: responsoryText, status: { la: 'verified', en: 'verified' } } : undefined,
     homily: homily
-      ? { source: withOccasion(homily.source, id), text: { text: homily.text, status: homily.status, citation: homily.citation } }
+      ? { source: withOccasion(homily.source, id, day), text: { text: homily.text, status: homily.status, citation: homily.citation } }
       : undefined,
   };
 }
@@ -948,10 +965,10 @@ function buildReadingPool(day: LiturgicalDay, temporalId: string, date: string,
         // apart by distributeIntoNocturns.
         const next = readings[i + 1];
         const homily = next && !next.isGospel && next.nocturn === reading.nocturn ? next : undefined;
-        bucket.push(gospelReadingPart(reading, homily, id, commonPoolIndex++));
+        bucket.push(gospelReadingPart(reading, homily, id, commonPoolIndex++, day));
         if (homily) i++;
       } else {
-        bucket.push(nocturnReadingPart(reading, id, commonPoolIndex++));
+        bucket.push(nocturnReadingPart(reading, id, commonPoolIndex++, day));
       }
       byGroup.set(groupKey, bucket);
     }