feat(desktop): add i18n infrastructure with react-intl (#8105)

ui/desktop/scripts/i18n-check.js

@@ -0,0 +1,37 @@
+#!/usr/bin/env node
+/**
+ * Cross-platform i18n check script.
+ * Extracts messages to a temp file and compares against the committed file
+ * to ensure src/i18n/messages/en.json is up to date.
+ */
+const fs = require('fs');
+const os = require('os');
+const path = require('path');
+const { execFileSync } = require('child_process');
+
+const projectDir = path.join(__dirname, '..');
+const formatjs = require.resolve('@formatjs/cli/bin/formatjs');
+const enFile = path.join(projectDir, 'src', 'i18n', 'messages', 'en.json');
+const tmpFile = path.join(os.tmpdir(), 'en.i18n-check.json');
+
+execFileSync(
+  process.execPath,
+  [formatjs, 'extract', 'src/**/*.{ts,tsx}', '--out-file', tmpFile, '--flatten'],
+  { stdio: 'inherit', cwd: projectDir }
+);
+
+const committed = fs.readFileSync(enFile, 'utf8');
+const extracted = fs.readFileSync(tmpFile, 'utf8');
+
+try {
+  fs.unlinkSync(tmpFile);
+} catch (_) {
+  // ignore cleanup errors
+}
+
+if (JSON.stringify(JSON.parse(committed)) !== JSON.stringify(JSON.parse(extracted))) {
+  console.error(
+    'Error: src/i18n/messages/en.json is out of date. Run pnpm i18n:extract to update it.'
+  );
+  process.exit(1);
+}

ui/desktop/scripts/i18n-compile.js

@@ -0,0 +1,27 @@
+#!/usr/bin/env node
+/**
+ * Cross-platform i18n compile script.
+ * Compiles all JSON message files in src/i18n/messages/ using formatjs.
+ */
+const fs = require('fs');
+const path = require('path');
+const { execFileSync } = require('child_process');
+
+const projectDir = path.join(__dirname, '..');
+const formatjs = require.resolve('@formatjs/cli/bin/formatjs');
+const messagesDir = path.join(projectDir, 'src', 'i18n', 'messages');
+const compiledDir = path.join(projectDir, 'src', 'i18n', 'compiled');
+
+fs.mkdirSync(compiledDir, { recursive: true });
+
+const files = fs.readdirSync(messagesDir).filter((f) => f.endsWith('.json'));
+
+for (const file of files) {
+  const locale = path.basename(file, '.json');
+  const inFile = path.join(messagesDir, file);
+  const outFile = path.join(compiledDir, `${locale}.json`);
+  execFileSync(process.execPath, [formatjs, 'compile', inFile, '--out-file', outFile], {
+    stdio: 'inherit',
+    cwd: projectDir,
+  });
+}