Bulk-author nameLa for all 299 remaining saints, close bilingual header backlog

Authors a real Latin nameLa for every saint in src/data/calendar/saints/
except the deliberate example-confessor placeholder (standard
ecclesiastical Latin forms, a lighter sourcing bar than this app's usual
reference-engine verification -- flagged for future spot-check). Fixes a
real mechanism bug found in the process: calendar/index.ts's sanctoral
collision-resolution branch was dropping nameLa for any saint that won
after beating another same-day candidate. Updates ~180 pre-existing test
fixtures across the calendar suite for the new field.

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

tests/calendar/february-sanctoral.test.ts

@@ -12,6 +12,7 @@ describe('February sanctoral pull (first pass)', () => {
       kind: 'sanctoral',
       id: 'st-dorothea',
       name: 'St. Dorothea, Virgin and Martyr',
+      nameLa: 'Sancta Dorothea, Virgo et Martyr',
       rank: 'simplex',
     });
     expect(getDayCollect(day).status.en).toBe('verified');
@@ -32,6 +33,7 @@ describe('February sanctoral pull (first pass)', () => {
       kind: 'sanctoral',
       id: 'st-agatha',
       name: 'St. Agatha, Virgin and Martyr',
+      nameLa: 'Sancta Agatha, Virgo et Martyr',
       rank: 'semiduplex',
     });
     const collect = getDayCollect(day);