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/billing/static/shared/js/upgrade-prompts.js

@@ -42,6 +42,11 @@
         loaded: false,
         error: null,
 
+        // Limit reached modal state
+        showLimitReachedConfirm: false,
+        limitReachedMessage: '',
+        limitReachedUpgradeUrl: null,
+
         // Computed-like getters
         get hasLimitsApproaching() {
             return this.usage?.has_limits_approaching || false;
@@ -193,18 +198,24 @@
             const limitName = limitNames[limitType] || limitType;
             const message = response.message || `You've reached your ${limitName} limit.`;
 
-            // Use browser confirm for simplicity - could be replaced with custom modal
-            const shouldUpgrade = confirm(
-                `${message}\n\n` +
-                `Current: ${response.current}/${response.limit}\n\n` +
+            const details = `${message} Current usage: ${response.current}/${response.limit}. ` +
                 (response.upgrade_tier_name
-                    ? `Upgrade to ${response.upgrade_tier_name} to get more ${limitName}.\n\nGo to billing page?`
-                    : 'Contact support for more capacity.')
-            );
+                    ? `Upgrade to ${response.upgrade_tier_name} to get more ${limitName}.`
+                    : 'Contact support for more capacity.');
 
-            if (shouldUpgrade && response.upgrade_tier_code) {
-                window.location.href = this.getBillingUrl();
+            this.limitReachedMessage = details;
+            this.limitReachedUpgradeUrl = response.upgrade_tier_code ? this.getBillingUrl() : null;
+            this.showLimitReachedConfirm = true;
+        },
+
+        /**
+         * Handle upgrade confirmation from limit reached modal
+         */
+        confirmUpgrade() {
+            if (this.limitReachedUpgradeUrl) {
+                window.location.href = this.limitReachedUpgradeUrl;
             }
+            this.showLimitReachedConfirm = false;
         },
 
         /**