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/tenancy/static/admin/js/platform-modules.js

@@ -65,6 +65,9 @@ function adminPlatformModules(platformCode) {
         },
 
         async init() {
+            // Load i18n translations
+            await I18n.loadModule('tenancy');
+
             // Guard against duplicate initialization
             if (window._platformModulesInitialized) {
                 moduleConfigLog.warn('Already initialized, skipping');
@@ -173,7 +176,7 @@ function adminPlatformModules(platformCode) {
         },
 
         async enableAll() {
-            if (!confirm('This will enable all modules. Continue?')) {
+            if (!confirm(I18n.t('tenancy.confirmations.enable_all_modules'))) {
                 return;
             }
 
@@ -204,7 +207,7 @@ function adminPlatformModules(platformCode) {
         },
 
         async disableOptional() {
-            if (!confirm('This will disable all optional modules, keeping only core modules. Continue?')) {
+            if (!confirm(I18n.t('tenancy.confirmations.disable_optional_modules'))) {
                 return;
             }