feat: multi-module improvements across merchant, store, i18n, and customer systems

- Fix platform-grouped merchant sidebar menu with core items at root level
- Add merchant store management (detail page, create store, team page)
- Fix store settings 500 error by removing dead stripe/API tab
- Move onboarding translations to module-owned locale files
- Fix onboarding banner i18n with server-side rendering + context inheritance
- Refactor login language selectors to use languageSelector() function (LANG-002)
- Move HTTPException handling to global exception handler in merchant routes (API-003)
- Add language selector to all login pages and portal headers
- Fix customer module: drop order stats from customer model, add to orders module
- Fix admin menu config visibility for super admin platform context
- Fix storefront auth and layout issues
- Add missing i18n translations for onboarding steps (en/fr/de/lb)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/modules/customers/static/store/js/customers.js

@@ -48,9 +48,7 @@ function storeCustomers() {
 
         // Modal states
         showDetailModal: false,
-        showOrdersModal: false,
         selectedCustomer: null,
-        customerOrders: [],
 
         // Debounce timer
         searchTimeout: null,
@@ -227,25 +225,6 @@ function storeCustomers() {
             }
         },
 
-        /**
-         * View customer orders
-         */
-        async viewCustomerOrders(customer) {
-            this.loading = true;
-            try {
-                const response = await apiClient.get(`/store/customers/${customer.id}/orders`);
-                this.selectedCustomer = customer;
-                this.customerOrders = response.orders || [];
-                this.showOrdersModal = true;
-                storeCustomersLog.info('Loaded customer orders:', customer.id, this.customerOrders.length);
-            } catch (error) {
-                storeCustomersLog.error('Failed to load customer orders:', error);
-                Utils.showToast(error.message || I18n.t('customers.messages.failed_to_load_customer_orders'), 'error');
-            } finally {
-                this.loading = false;
-            }
-        },
-
         /**
          * Send message to customer
          */
@@ -275,19 +254,6 @@ function storeCustomers() {
             });
         },
 
-        /**
-         * Format price for display
-         */
-        formatPrice(cents) {
-            if (!cents && cents !== 0) return '-';
-            const locale = window.STORE_CONFIG?.locale || 'en-GB';
-            const currency = window.STORE_CONFIG?.currency || 'EUR';
-            return new Intl.NumberFormat(locale, {
-                style: 'currency',
-                currency: currency
-            }).format(cents / 100);
-        },
-
         /**
          * Pagination: Previous page
          */