propers: add December's collect and antiphon text

10 collects, 5 antiphons -- including backfilling the pre-existing
Immaculate Conception entry. St. Damasus's collect is Latin-only (no
English translation exists in the reference source at all); a few
others (All Saints, Bibiana, Immaculate Conception) needed their English
read directly from the raw source file after the live query's English
side either omitted the Oratio translation or rendered the wrong Marian
feast's text -- caught by cross-checking, not assumed.

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

tests/calendar/december-sanctoral.test.ts

@@ -0,0 +1,95 @@
+import { describe, expect, it } from 'vitest';
+import { resolveDay } from '../../src/calendar';
+import { getDayCollect } from '../../src/hours/resolve-common';
+
+// Clean per-annum years for these dates (no Sunday collision) — see
+// data/calendar/saints/*.yml for per-saint source detail.
+describe('December sanctoral pull (first pass, 12/12)', () => {
+  it('a Simplex saint on an ordinary Advent feria is only ever commemorated, the feria itself staying primary', () => {
+    const day = resolveDay('2025-12-02');
+    expect(day.winner.kind).toBe('temporal');
+    expect(day.commemorations).toEqual([
+      { kind: 'sanctoral', id: 'st-bibiana', name: 'St. Bibiana, Virgin and Martyr', rank: 'simplex' },
+    ]);
+    // The feria wins, so the day's collect is the governing Sunday's own
+    // (already authored), not St. Bibiana's (which has none) -- the
+    // commemoration is real but doesn't change which collect is prayed.
+    expect(getDayCollect(day).status.en).toBe('verified');
+  });
+
+  it('a Semiduplex saint wins outright over an ordinary Advent feria, which is commemorated in return, with a real proper collect', () => {
+    const day = resolveDay('2025-12-06');
+    expect(day.winner).toEqual({
+      kind: 'sanctoral',
+      id: 'st-nicholas',
+      name: 'St. Nicholas, Bishop and Confessor',
+      rank: 'semiduplex',
+    });
+    expect(day.commemorations.length).toBe(1);
+    expect(day.commemorations[0]?.kind).toBe('temporal');
+    expect(getDayCollect(day).status.en).toBe('verified');
+  });
+
+  it('the Immaculate Conception wins outright with a real proper collect and antiphon, backfilled this month', () => {
+    const day = resolveDay('2025-12-08');
+    expect(day.winner).toEqual({
+      kind: 'sanctoral',
+      id: 'immaculate-conception',
+      name: 'The Immaculate Conception of the Blessed Virgin Mary',
+      rank: 'duplex-1-classis',
+    });
+    expect(getDayCollect(day).status.en).toBe('verified');
+  });
+
+  it('St. Thomas the Apostle wins outright with a real proper collect and antiphon, distinct from his own Vigil on Advent Ember Saturday', () => {
+    const day = resolveDay('2026-12-21');
+    expect(day.winner).toEqual({
+      kind: 'sanctoral',
+      id: 'st-thomas-apostle',
+      name: 'St. Thomas, Apostle',
+      rank: 'duplex-2-classis',
+    });
+    expect(getDayCollect(day).status.en).toBe('verified');
+  });
+
+  it('the Christmas Octave "Comites Christi" days each win outright with real propers, the Octave day commemorated in return', () => {
+    const stephen = resolveDay('2025-12-26');
+    const john = resolveDay('2025-12-27');
+    const innocents = resolveDay('2026-12-28');
+    expect(stephen.winner).toEqual({
+      kind: 'sanctoral',
+      id: 'st-stephen-protomartyr',
+      name: 'St. Stephen, Protomartyr',
+      rank: 'duplex-2-classis',
+    });
+    expect(john.winner).toEqual({
+      kind: 'sanctoral',
+      id: 'st-john-apostle',
+      name: 'St. John, Apostle and Evangelist',
+      rank: 'duplex-2-classis',
+    });
+    expect(innocents.winner).toEqual({
+      kind: 'sanctoral',
+      id: 'holy-innocents',
+      name: 'The Holy Innocents, Martyrs',
+      rank: 'duplex-2-classis',
+    });
+    for (const day of [stephen, john, innocents]) {
+      expect(day.commemorations.length).toBe(1);
+      expect(day.commemorations[0]?.kind).toBe('temporal');
+      expect(getDayCollect(day).status.en).toBe('verified');
+    }
+  });
+
+  it('St. Thomas of Canterbury, only Semiduplex, still wins outright within the Christmas Octave -- the concrete case behind this month\'s temporal-category fix', () => {
+    const day = resolveDay('2025-12-29');
+    expect(day.winner).toEqual({
+      kind: 'sanctoral',
+      id: 'st-thomas-becket',
+      name: 'St. Thomas of Canterbury, Bishop and Martyr',
+      rank: 'semiduplex',
+    });
+    expect(day.commemorations.length).toBe(1);
+    expect(day.commemorations[0]?.kind).toBe('temporal');
+  });
+});