ci(workflow): validate i18n locale files are synchronized (#2347)

bin/check-i18n.js

@@ -0,0 +1,39 @@
+#!/usr/bin/env node
+
+/**
+ * Check that i18n locale files are in sync with extracted messages.
+ * Runs `pnpm i18n:extract` and compares en.json; exits 1 if they differ.
+ */
+const { execSync } = require('child_process');
+const fs = require('fs');
+const path = require('path');
+
+const localePath = path.join(
+  __dirname,
+  '..',
+  'src',
+  'i18n',
+  'locale',
+  'en.json'
+);
+const backupPath = `${localePath}.bak`;
+
+try {
+  fs.copyFileSync(localePath, backupPath);
+  execSync('pnpm i18n:extract', { stdio: 'inherit' });
+  const original = fs.readFileSync(backupPath, 'utf8');
+  const extracted = fs.readFileSync(localePath, 'utf8');
+  fs.unlinkSync(backupPath);
+
+  if (original !== extracted) {
+    console.error(
+      "i18n messages are out of sync. Please run 'pnpm i18n:extract' and commit the changes."
+    );
+    process.exit(1);
+  }
+} catch (err) {
+  if (fs.existsSync(backupPath)) {
+    fs.unlinkSync(backupPath);
+  }
+  throw err;
+}