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/painting.json

@@ -0,0 +1,11 @@
+{
+  "aboutArtist": "About {{name}}",
+  "influencedBy": "Influenced By",
+  "influenced": "Influenced",
+  "noInfluences": "No documented influences for this work.",
+  "noInfluencedWorks": "No documented works influenced by this painting yet.",
+  "catalogPosition": "Catalog position",
+  "lightboxHint": "Click anywhere to close",
+  "prevPainting": "Previous painting",
+  "nextPainting": "Next painting"
+}