Add nameLa mechanism for bilingual header, proof set of 11 feasts + St. Lawrence

Threads an optional nameLa field through SanctoralIdentity/SaintRecord/
TemporalFeastRecord/ActiveOctave so day-label.ts can render real Latin
proper names instead of always falling back to English. Authors the
proof set: all 11 named temporal feasts plus St. Lawrence (chosen to
exercise the octave-headline and octave-commemoration code paths too).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EwsZQMjALCvy7u9tFDWmuQ

tests/calendar/december-sanctoral.test.ts

@@ -84,7 +84,7 @@ describe('December sanctoral pull (first pass, 12/12)', () => {
     // dedicated stacking test below for the full week's build-up.
     expect(stephen.commemorations).toEqual([
       { kind: 'temporal', id: expect.any(String) },
-      { kind: 'octave', id: 'christmas-day', name: 'Christmas' },
+      { kind: 'octave', id: 'christmas-day', name: 'Christmas', nameLa: 'Nativitas Domini' },
     ]);
   });
 
@@ -101,7 +101,7 @@ describe('December sanctoral pull (first pass, 12/12)', () => {
     // all stacked up and commemorate alongside him.
     expect(day.commemorations).toEqual([
       { kind: 'temporal', id: expect.any(String) },
-      { kind: 'octave', id: 'christmas-day', name: 'Christmas' },
+      { kind: 'octave', id: 'christmas-day', name: 'Christmas', nameLa: 'Nativitas Domini' },
       { kind: 'octave', id: 'st-stephen-protomartyr', name: 'St. Stephen, Protomartyr' },
       { kind: 'octave', id: 'st-john-apostle', name: 'St. John, Apostle and Evangelist' },
       { kind: 'octave', id: 'holy-innocents', name: 'The Holy Innocents, Martyrs' },
@@ -155,7 +155,7 @@ describe('December sanctoral pull (first pass, 12/12)', () => {
     const dec30 = resolveDay('2033-12-30'); // no saint of its own -- a plain Octave-of-the-Nativity day
     expect(dec30.winner.kind).toBe('temporal');
     expect(dec30.commemorations).toEqual([
-      { kind: 'octave', id: 'christmas-day', name: 'Christmas' },
+      { kind: 'octave', id: 'christmas-day', name: 'Christmas', nameLa: 'Nativitas Domini' },
       { kind: 'octave', id: 'st-stephen-protomartyr', name: 'St. Stephen, Protomartyr' },
       { kind: 'octave', id: 'st-john-apostle', name: 'St. John, Apostle and Evangelist' },
       { kind: 'octave', id: 'holy-innocents', name: 'The Holy Innocents, Martyrs' },