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

src/data/calendar/saints/ss-seven-brothers-rufina-and-secunda.yml

@@ -3,6 +3,7 @@
 # Own proper collect, no unique antiphon of their own.
 id: ss-seven-brothers-rufina-and-secunda
 name: "Ss. Seven Brothers, Martyrs, and Ss. Rufina and Secunda, Virgins and Martyrs"
+nameLa: "Septem Fratres, Martyres, et Sanctæ Rufina et Secunda, Virgines et Martyres"
 rank: semiduplex
 common: common-of-several-martyrs
 propers: "ss-seven-brothers-rufina-and-secunda"