refactor: complete JS i18n migration for confirm dialogs and toast messages

Migrate 34 hardcoded user-facing strings to use I18n.t() for translation:

- CMS: media file operations (5 strings)
- Marketplace: Letzshop integration (16 strings)
- Messaging: notifications, messages, email templates (5 strings)
- Tenancy: platform modules, menu config, theme (5 strings)
- Core: menu config, settings, storefront cart (5 strings)
- Catalog: product creation (3 strings)
- Utils: clipboard operations (2 strings)

Added confirmations and messages keys to module locale files.
Added I18n.loadModule() calls to JS files that were missing them.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/modules/messaging/locales/en.json

@@ -1 +1,49 @@
-{}
+{
+  "notifications": {
+    "title": "Notifications",
+    "mark_read": "Mark as Read",
+    "mark_all_read": "Mark All as Read",
+    "no_notifications": "No notifications",
+    "new_order": "New Order",
+    "order_updated": "Order Updated",
+    "low_stock": "Low Stock Alert",
+    "import_complete": "Import Complete",
+    "import_failed": "Import Failed"
+  },
+  "messages": {
+    "failed_to_load_template": "Failed to load template",
+    "template_saved_successfully": "Template saved successfully",
+    "reverted_to_platform_default": "Reverted to platform default",
+    "failed_to_load_preview": "Failed to load preview",
+    "failed_to_send_test_email": "Failed to send test email",
+    "failed_to_load_conversations": "Failed to load conversations",
+    "failed_to_load_conversation": "Failed to load conversation",
+    "conversation_closed": "Conversation closed",
+    "failed_to_close_conversation": "Failed to close conversation",
+    "conversation_reopened": "Conversation reopened",
+    "failed_to_reopen_conversation": "Failed to reopen conversation",
+    "conversation_created": "Conversation created",
+    "notification_marked_as_read": "Notification marked as read",
+    "all_notifications_marked_as_read": "All notifications marked as read",
+    "notification_deleted": "Notification deleted",
+    "notification_settings_saved": "Notification settings saved",
+    "failed_to_load_templates": "Failed to load templates",
+    "failed_to_load_recipients": "Failed to load recipients",
+    "failed_to_load_notifications": "Failed to load notifications",
+    "failed_to_mark_notification_as_read": "Failed to mark notification as read",
+    "failed_to_mark_all_as_read": "Failed to mark all as read",
+    "failed_to_delete_notification": "Failed to delete notification",
+    "failed_to_load_alerts": "Failed to load alerts",
+    "alert_resolved_successfully": "Alert resolved successfully",
+    "failed_to_resolve_alert": "Failed to resolve alert",
+    "no_template_for_language": "No template for {language} - create one by saving",
+    "failed_to_save_template": "Failed to save template",
+    "test_email_sent": "Test email sent to {email}"
+  },
+  "confirmations": {
+    "delete_notification": "Are you sure you want to delete this notification?",
+    "close_conversation": "Close this conversation?",
+    "close_conversation_admin": "Are you sure you want to close this conversation?",
+    "delete_customization": "Are you sure you want to delete your customization and revert to the platform default?"
+  }
+}