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/catalog/static/vendor/js/product-create.js

@@ -44,6 +44,9 @@ function vendorProductCreate() {
         },
 
         async init() {
+            // Load i18n translations
+            await I18n.loadModule('catalog');
+
             // Guard against duplicate initialization
             if (window._vendorProductCreateInitialized) return;
             window._vendorProductCreateInitialized = true;
@@ -66,7 +69,7 @@ function vendorProductCreate() {
 
         async createProduct() {
             if (!this.form.title || !this.form.price) {
-                this.showToast('Title and price are required', 'error');
+                Utils.showToast(I18n.t('catalog.messages.title_and_price_required'), 'error');
                 return;
             }
 
@@ -93,7 +96,7 @@ function vendorProductCreate() {
                 }
 
                 vendorProductCreateLog.info('Product created:', response.data);
-                this.showToast('Product created successfully', 'success');
+                Utils.showToast(I18n.t('catalog.messages.product_created_successfully'), 'success');
 
                 // Navigate back to products list
                 setTimeout(() => {
@@ -102,8 +105,8 @@ function vendorProductCreate() {
 
             } catch (err) {
                 vendorProductCreateLog.error('Failed to create product:', err);
-                this.error = err.message || 'Failed to create product';
-                this.showToast(this.error, 'error');
+                this.error = err.message || I18n.t('catalog.messages.failed_to_create_product');
+                Utils.showToast(this.error, 'error');
             } finally {
                 this.saving = false;
             }