perf(modal): unify cancellable frontend modal flows

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/Core/DBMigratorPart2.php

@@ -180,6 +180,7 @@ trait DBMigratorPart2 {
             PRIMARY KEY  (id),
             UNIQUE KEY uniq_order_number (order_number),
             KEY idx_user (user_id),
+            KEY idx_user_status_created (user_id, status, created_at),
             KEY idx_status (status),
             KEY idx_created (created_at),
             KEY idx_product (product_type, product_id)