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>

scripts/migrate-i18n.js

@@ -0,0 +1,17 @@
+require('dotenv').config();
+const fs = require('fs');
+const path = require('path');
+const pool = require('../server/db');
+
+async function main() {
+  const sqlPath = path.join(__dirname, '../db/migrate-i18n.sql');
+  const sql = fs.readFileSync(sqlPath, 'utf8');
+  await pool.query(sql);
+  console.log('entity_translations table ready');
+  await pool.end();
+}
+
+main().catch((err) => {
+  console.error(err);
+  process.exit(1);
+});