feat(product): 恢復並實作商品起停用狀態功能，包含表單開關與列表顯示

app/Modules/Inventory/Models/Product.php

@@ -31,10 +31,12 @@ class Product extends Model
         'price',
         'member_price',
         'wholesale_price',
+        'is_active',
     ];
 
     protected $casts = [
         'conversion_rate' => 'decimal:4',
+        'is_active' => 'boolean',
     ];
 
     /**