fix: replace all native confirm() dialogs with styled modal macros

Migrated ~68 native browser confirm() calls across 74 files to use the
project's confirm_modal/confirm_modal_dynamic Jinja2 macros, providing
consistent styled confirmation dialogs instead of plain browser popups.

Modules updated: core, tenancy, cms, marketplace, messaging, billing,
customers, orders, cart. Uses danger/warning/info variants and
double-confirm pattern for destructive delete operations.

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

app/modules/tenancy/static/admin/js/merchants.js

@@ -26,6 +26,10 @@ function adminMerchants() {
         loading: false,
         error: null,
 
+        // Modal state
+        showDeleteMerchantModal: false,
+        merchantToDelete: null,
+
         // Search and filters
         filters: {
             search: '',
@@ -192,23 +196,19 @@ function adminMerchants() {
             window.location.href = `/admin/merchants/${merchantId}/edit`;
         },
 
-        // Delete merchant
-        async deleteMerchant(merchant) {
+        // Prompt delete merchant modal
+        promptDeleteMerchant(merchant) {
             if (merchant.store_count > 0) {
                 merchantsLog.warn('Cannot delete merchant with stores');
                 Utils.showToast(`Cannot delete "${merchant.name}" because it has ${merchant.store_count} store(s). Please delete or reassign the stores first.`, 'warning');
                 return;
             }
+            this.merchantToDelete = merchant;
+            this.showDeleteMerchantModal = true;
+        },
 
-            const confirmed = confirm(
-                `Are you sure you want to delete "${merchant.name}"?\n\nThis action cannot be undone.`
-            );
-
-            if (!confirmed) {
-                merchantsLog.info('Delete cancelled by user');
-                return;
-            }
-
+        // Delete merchant
+        async deleteMerchant(merchant) {
             try {
                 merchantsLog.info('Deleting merchant:', merchant.id);