Add missing i18n translation files

These files are required by the application but were missing from the repository.
Created default locale and translation stubs to enable SSR bundles to build successfully.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: justin808

client/app/libs/i18n/default.js

@@ -0,0 +1,9 @@
+// Default locale and messages for i18n
+export const defaultLocale = 'en';
+
+export const defaultMessages = {
+  'app.name': 'React Webpack Rails Tutorial',
+  'comment.form.name_label': 'Name',
+  'comment.form.text_label': 'Text',
+  'comment.form.submit': 'Submit',
+};

client/app/libs/i18n/translations.js

@@ -0,0 +1,15 @@
+// Translation messages for different locales
+export const translations = {
+  en: {
+    'app.name': 'React Webpack Rails Tutorial',
+    'comment.form.name_label': 'Name',
+    'comment.form.text_label': 'Text',
+    'comment.form.submit': 'Submit',
+  },
+  es: {
+    'app.name': 'Tutorial de React Webpack Rails',
+    'comment.form.name_label': 'Nombre',
+    'comment.form.text_label': 'Texto',
+    'comment.form.submit': 'Enviar',
+  },
+};