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/ember-days.test.ts

@@ -20,6 +20,7 @@ describe('Ember days', () => {
       kind: 'sanctoral',
       id: 'ss-cornelius-and-cyprian',
       name: 'Ss. Cornelius, Pope, and Cyprian, Bishop, Martyrs',
+      nameLa: 'Sanctus Cornelius, Papa, et Sanctus Cyprianus, Episcopus, Martyres',
       rank: 'semiduplex',
     });
     expect(day.commemorations).toContainEqual({ kind: 'temporal', id: 'ember-september-wednesday' });