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/core/static/admin/js/my-menu-config.js

@@ -57,6 +57,9 @@ function adminMyMenuConfig() {
         },
 
         async init() {
+            // Load i18n translations
+            await I18n.loadModule('core');
+
             // Guard against multiple initialization
             if (window._adminMyMenuConfigInitialized) {
                 myMenuConfigLog.warn('Already initialized, skipping');
@@ -141,7 +144,7 @@ function adminMyMenuConfig() {
         },
 
         async showAll() {
-            if (!confirm('This will show all menu items. Continue?')) {
+            if (!confirm(I18n.t('core.confirmations.show_all_menu_items'))) {
                 return;
             }
 
@@ -163,7 +166,7 @@ function adminMyMenuConfig() {
         },
 
         async resetToDefaults() {
-            if (!confirm('This will hide all menu items (except mandatory ones). You can then enable the ones you want. Continue?')) {
+            if (!confirm(I18n.t('core.confirmations.hide_all_menu_items'))) {
                 return;
             }
 

app/modules/core/static/admin/js/settings.js

@@ -82,6 +82,9 @@ function adminSettings() {
         testEmailSuccess: null,
 
         async init() {
+            // Load i18n translations
+            await I18n.loadModule('core');
+
             // Guard against multiple initialization
             if (window._adminSettingsInitialized) return;
             window._adminSettingsInitialized = true;
@@ -434,7 +437,7 @@ function adminSettings() {
         },
 
         async resetEmailSettings() {
-            if (!confirm('This will reset all email settings to use .env defaults. Continue?')) {
+            if (!confirm(I18n.t('core.confirmations.reset_email_settings'))) {
                 return;
             }
 

app/modules/core/static/storefront/js/storefront-layout.js

@@ -153,13 +153,13 @@ function shopLayoutData() {
         removeFromCart(productId) {
             this.cart = this.cart.filter(item => item.id !== productId);
             this.saveCart();
-            this.showToast('Item removed from cart', 'info');
+            this.showToast(I18n.t('core.messages.item_removed_from_cart'), 'info');
         },
 
         clearCart() {
             this.cart = [];
             this.saveCart();
-            this.showToast('Cart cleared', 'info');
+            this.showToast(I18n.t('core.messages.cart_cleared'), 'info');
         },
 
         saveCart() {