Add Vespers' ferial Preces, sourced from Tridentine 1906/1910

Monastic 1617 has no ferial Preces at Vespers, same gap Lauds already
had — the fuller "Preces feriales Vespera" is byte-for-byte the Lauds
ferial Preces with Psalm 129 swapped for Psalm 50 in the source, live-
verified against the same clean Advent feria already used for Lauds.
The short Sunday/feast form turns out to be identical at both hours too,
so it's reused directly rather than duplicated.

Factors the shared ferial-or-vigil predicate out of hours/lauds.ts into
resolve-common.ts's isFerialOrVigil so both hours' -preces cases resolve
it the same way instead of keeping two copies in sync by hand.

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

src/hours/compline.ts

@@ -94,6 +94,7 @@ function resolvePart(part: HourPart, day: LiturgicalDay): ResolvedPart[] {
     case 'vespers-psalmody':
     case 'vespers-office':
     case 'magnificat':
+    case 'vespers-preces':
       throw new Error(`Compline's ordo doesn't support a '${part.kind}' part`);
   }
 }

src/hours/lauds.ts

@@ -18,6 +18,7 @@ import {
   ALWAYS_OVERRIDE_TEMPORAL_IDS,
   verifiedText,
   seasonalOfficeSuffix,
+  isFerialOrVigil,
 } from './resolve-common';
 import laudsDefinitionData from '../data/hours/lauds.yml';
 import laudsAntiphonsData from '../data/hours/lauds-antiphons.yml';
@@ -317,25 +318,7 @@ function resolvePart(part: HourPart, day: LiturgicalDay): ResolvedPart[] {
       return [{ kind: 'preces', text: resolveCommon(id), label: getMarianAntiphonLabel(id) }];
     }
     case 'lauds-preces': {
-      // Deliberately not `isSundayOrFeast` -- that treats any sanctoral
-      // winner, Vigils included, as a "feast." Here a Vigil needs to land
-      // on the ferial side instead (per direct instruction), so it's
-      // checked for explicitly: a Vigil-ranked sanctoral winner, or a
-      // bare temporal winner that isn't Sunday and isn't a named
-      // temporal identity like Marian Saturday or Christ the King (which
-      // aren't Sunday or a sanctoral winner either, but still aren't a
-      // bare ferial office -- same reasoning as the Cross suffrage's own
-      // gate just above). Also excludes any day within an active octave
-      // -- live-verified (Tridentine 1910, day 3 of St. Lawrence's own
-      // octave): "Preces Feriales{omittitur}", same exclusion the
-      // suffrages already have, for the same reason -- an octave day
-      // isn't a bare ferial office even though nothing else is winning
-      // it outright.
-      const isVigil = day.winner.kind === 'sanctoral' && day.winner.rank === 'vigil';
-      const isBareFeria = day.winner.kind === 'temporal' && !getTemporalFeastRecord(day.winner.id);
-      const isWithinAnOctave = activeOctavesFor(day.date).length > 0;
-      const isFerialOrVigil = day.weekday !== 'sunday' && !isWithinAnOctave && (isVigil || isBareFeria);
-      const id = isFerialOrVigil ? 'lauds-preces-feriales' : 'lauds-short-litany';
+      const id = isFerialOrVigil(day) ? 'lauds-preces-feriales' : 'lauds-short-litany';
       return [{ kind: 'preces', text: resolveCommon(id) }];
     }
     // Not used by Lauds.
@@ -354,6 +337,7 @@ function resolvePart(part: HourPart, day: LiturgicalDay): ResolvedPart[] {
     case 'vespers-psalmody':
     case 'vespers-office':
     case 'magnificat':
+    case 'vespers-preces':
       throw new Error(`Lauds' ordo doesn't support a '${part.kind}' part`);
   }
 }

src/hours/none.ts

@@ -70,6 +70,7 @@ function resolvePart(part: HourPart, day: LiturgicalDay): ResolvedPart[] {
     case 'vespers-psalmody':
     case 'vespers-office':
     case 'magnificat':
+    case 'vespers-preces':
       throw new Error(`None's ordo doesn't support a '${part.kind}' part`);
   }
 }

src/hours/prime.ts

@@ -126,6 +126,7 @@ function resolvePart(part: HourPart, date: string, day: LiturgicalDay): Resolved
     case 'vespers-psalmody':
     case 'vespers-office':
     case 'magnificat':
+    case 'vespers-preces':
       throw new Error(`Prime's ordo doesn't support a '${part.kind}' part`);
   }
 }

src/hours/resolve-common.ts

@@ -3,7 +3,8 @@ import type { Commemoration, DayWinner, LiturgicalDay, Weekday } from '../calend
 import type { ProperText } from '../propers';
 import { getCommonProper, getTemporalProper } from '../propers';
 import { getSaintRecord } from '../calendar/feasts';
-import { resolveActiveOctave } from '../calendar';
+import { resolveActiveOctave, activeOctavesFor } from '../calendar';
+import { getTemporalFeastRecord } from '../calendar/temporal-feasts';
 import { splitAntiphon } from './antiphon';
 import vespersMagnificatAntiphonsData from '../data/hours/vespers-magnificat-antiphons.yml';
 
@@ -105,6 +106,31 @@ export function isSundayOrFeastOffice(day: LiturgicalDay): boolean {
   return day.weekday === 'sunday' || resolveOfficeWinner(day).kind === 'sanctoral';
 }
 
+/**
+ * A day/hour is "ferial or vigil" — the predicate both Lauds' and Vespers'
+ * ferial Preces (`lauds-preces`/`vespers-preces`) key off to pick the
+ * fuller Tridentine 1906/1910 litany over the short Sunday/feast one.
+ * Deliberately not `isSundayOrFeast`/`isSundayOrFeastOffice` — those treat
+ * any sanctoral winner, Vigils included, as a "feast." Here a Vigil needs
+ * to land on the ferial side instead (per direct instruction), so it's
+ * checked for explicitly: a Vigil-ranked sanctoral winner, or a bare
+ * temporal winner that isn't Sunday and isn't a named temporal identity
+ * like Marian Saturday or Christ the King (which aren't Sunday or a
+ * sanctoral winner either, but still aren't a bare ferial office — same
+ * reasoning as Lauds' own Cross-suffrage gate). Also excludes any day
+ * within an active octave — live-verified (Tridentine 1910, day 3 of St.
+ * Lawrence's own octave, both Lauds and Vespers): "Preces Feriales
+ * {omittitur}", same exclusion the suffrages already have, for the same
+ * reason — an octave day isn't a bare ferial office even though nothing
+ * else is winning it outright.
+ */
+export function isFerialOrVigil(day: LiturgicalDay): boolean {
+  const isVigil = day.winner.kind === 'sanctoral' && day.winner.rank === 'vigil';
+  const isBareFeria = day.winner.kind === 'temporal' && !getTemporalFeastRecord(day.winner.id);
+  const isWithinAnOctave = activeOctavesFor(day.date).length > 0;
+  return day.weekday !== 'sunday' && !isWithinAnOctave && (isVigil || isBareFeria);
+}
+
 /**
  * The id to look up for today's office winner's (resolveOfficeWinner)
  * minor-hour content (antiphon + chapter) — `${hourId}-antiphon-${id}`/

src/hours/sext.ts

@@ -70,6 +70,7 @@ function resolvePart(part: HourPart, day: LiturgicalDay): ResolvedPart[] {
     case 'vespers-psalmody':
     case 'vespers-office':
     case 'magnificat':
+    case 'vespers-preces':
       throw new Error(`Sext's ordo doesn't support a '${part.kind}' part`);
   }
 }

src/hours/terce.ts

@@ -70,6 +70,7 @@ function resolvePart(part: HourPart, day: LiturgicalDay): ResolvedPart[] {
     case 'vespers-psalmody':
     case 'vespers-office':
     case 'magnificat':
+    case 'vespers-preces':
       throw new Error(`Terce's ordo doesn't support a '${part.kind}' part`);
   }
 }

src/hours/types.ts

@@ -155,6 +155,19 @@ export type HourPart =
   // deliberately not the shared `isSundayOrFeast` (a Vigil counts as a
   // "feast" there; here it needs to count as ferial-like instead).
   | { kind: 'lauds-preces' }
+  // Vespers only. Mirrors 'lauds-preces' exactly — the Tridentine
+  // 1906/1910 "Preces feriales Vespera" (source: `@:Preces feriales
+  // Laudes:s/129/50/` — byte-for-byte the Lauds ferial Preces with Psalm
+  // 129 swapped for Psalm 50, live-verified against a clean Advent feria
+  // 2026-12-17) on a ferial or vigil day, replacing the short Sunday/feast
+  // litany otherwise said before the day's collect(s) — see hours/
+  // resolve-common.ts's isFerialOrVigil (shared with 'lauds-preces') and
+  // hours/vespers.ts's 'vespers-preces' case. Unlike Lauds, the short form
+  // here reuses `lauds-short-litany` directly rather than a Vespers-named
+  // duplicate — confirmed byte-identical by live query at both hours,
+  // same reuse discipline as data/hours/vespers.yml's `lauds-conclusio`
+  // closing.
+  | { kind: 'vespers-preces' }
   // Lauds/Vespers. The day's own collect *and* one more per commemoration
   // (calendar/types.ts's LiturgicalDay.commemorations) — see hours/
   // resolve-common.ts's getDayCollects. Distinct from the singular

src/hours/vespers.ts

@@ -13,6 +13,7 @@ import {
   resolveOfficeWinner,
   verifiedText,
   seasonalOfficeSuffix,
+  isFerialOrVigil,
 } from './resolve-common';
 import vespersDefinitionData from '../data/hours/vespers.yml';
 import vespersAntiphonsData from '../data/hours/vespers-antiphons.yml';
@@ -122,6 +123,10 @@ function resolvePart(part: HourPart, day: LiturgicalDay): ResolvedPart[] {
         { kind: 'antiphon', text: full },
       ];
     }
+    case 'vespers-preces': {
+      const id = isFerialOrVigil(day) ? 'vespers-preces-feriales' : 'lauds-short-litany';
+      return [{ kind: 'preces', text: resolveCommon(id) }];
+    }
     case 'day-collects':
       return getDayCollects(day);
     case 'preces':