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/cms/static/vendor/js/media.js

@@ -119,6 +119,9 @@ function vendorMedia() {
         uploadingFiles: [],
 
         async init() {
+            // Load i18n translations
+            await I18n.loadModule('cms');
+
             // Guard against duplicate initialization
             if (window._vendorMediaInitialized) return;
             window._vendorMediaInitialized = true;
@@ -233,7 +236,7 @@ function vendorMedia() {
                 });
 
                 if (response.ok) {
-                    this.showToast('Media updated successfully', 'success');
+                    Utils.showToast(I18n.t('cms.messages.media_updated_successfully'), 'success');
                     this.showDetailModal = false;
                     await this.loadMedia();
                 } else {
@@ -250,7 +253,7 @@ function vendorMedia() {
         async deleteMedia() {
             if (!this.selectedMedia) return;
 
-            if (!confirm('Are you sure you want to delete this file? This cannot be undone.')) {
+            if (!confirm(I18n.t('cms.confirmations.delete_file'))) {
                 return;
             }
 
@@ -260,7 +263,7 @@ function vendorMedia() {
                 const response = await apiClient.delete(`/vendor/media/${this.selectedMedia.id}`);
 
                 if (response.ok) {
-                    this.showToast('Media deleted successfully', 'success');
+                    Utils.showToast(I18n.t('cms.messages.media_deleted_successfully'), 'success');
                     this.showDetailModal = false;
                     this.selectedMedia = null;
                     await this.loadMedia();
@@ -351,9 +354,9 @@ function vendorMedia() {
         copyToClipboard(text) {
             if (!text) return;
             navigator.clipboard.writeText(text).then(() => {
-                this.showToast('URL copied to clipboard', 'success');
+                Utils.showToast(I18n.t('cms.messages.url_copied_to_clipboard'), 'success');
             }).catch(() => {
-                this.showToast('Failed to copy URL', 'error');
+                Utils.showToast(I18n.t('cms.messages.failed_to_copy_url'), 'error');
             });
         }
     };