feat(cart): implement cart editing policies and update related functionality

app/Domains/Tenant/Enums/CartEditingPolicy.php

@@ -0,0 +1,32 @@
+<?php
+
+namespace App\Domains\Tenant\Enums;
+
+enum CartEditingPolicy: string
+{
+    case Disabled = 'disabled';
+    case QuantityAndRemove = 'quantity_and_remove';
+    case Full = 'full';
+
+    public function allowsQuantityChanges(): bool
+    {
+        return $this !== self::Disabled;
+    }
+
+    public function allowsRemoval(): bool
+    {
+        return $this !== self::Disabled;
+    }
+
+    public function allowsVariantChanges(): bool
+    {
+        return $this === self::Full;
+    }
+
+    public function allowsModification(): bool
+    {
+        return $this->allowsRemoval()
+            || $this->allowsQuantityChanges()
+            || $this->allowsVariantChanges();
+    }
+}