Add Russian i18n with DB translations, locale API, and curator review UI.

UI chrome via react-i18next, catalog text in entity_translations with ru.wikipedia seeding, locale-aware search, and Translations page for publish workflow.

Co-authored-by: Cursor <cursoragent@cursor.com>

server/migrate.js

@@ -14,6 +14,7 @@ const INCREMENTAL_MIGRATIONS = [
   'migrate-perf-indexes.sql',
   'migrate-search.sql',
   'migrate-sync-timestamps.sql',
+  'migrate-i18n.sql',
 ];
 
 async function bootstrapCurator() {