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>

client/src/locales/en/translations.json

@@ -0,0 +1,20 @@
+{
+  "title": "Translation review",
+  "back": "← Back to gallery",
+  "locale": "Locale",
+  "entityType": "Entity type",
+  "status": "Status",
+  "all": "All",
+  "draft": "Draft",
+  "reviewed": "Reviewed",
+  "published": "Published",
+  "coverage": "Coverage",
+  "artistsBio": "Artists with bio (ru)",
+  "paintingsTitle": "Paintings with title alias (ru)",
+  "canonical": "English (canonical)",
+  "translation": "Translation",
+  "saveDraft": "Save draft",
+  "publish": "Publish",
+  "noRows": "No translation rows match the filter.",
+  "loadFailed": "Failed to load translations"
+}