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-twelve-brothers.yml

@@ -4,6 +4,7 @@
 # tested year. rank/propers unverified placeholders.
 id: ss-twelve-brothers
 name: "Ss. Twelve Brothers, Martyrs"
+nameLa: "Duodecim Fratres, Martyres"
 rank: simplex
 common: common-of-several-martyrs
 propers: "ss-twelve-brothers"