refactor(checkout): disable purchase item editing

database/migrations/2026_08_21_000000_disable_checkout_item_editing.php

@@ -0,0 +1,20 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Support\Facades\DB;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        DB::table('tenants')->update([
+            'checkout_editing_policy' => 'disabled',
+        ]);
+    }
+
+    public function down(): void
+    {
+        // Checkout editing stays disabled because previous tenant values cannot
+        // be reconstructed after normalization.
+    }
+};