Fix licensed variable products showing as sold out (v0.5.11)

- Fixed is_purchasable() method in LicensedVariableProduct to delegate to
  parent WC_Product_Variable instead of checking for price (variable products
  don't have direct prices, only their variations do)
- Fixed getProductClass() filter to accept all 4 WooCommerce parameters
  and use product_id for reliable variation parent detection
- Fallback to global $post when product_id not available for backwards compat

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/Product/LicensedProductType.php

@@ -32,7 +32,7 @@ final class LicensedProductType
     {
         // Register product types
         add_filter('product_type_selector', [$this, 'addProductType']);
-        add_filter('woocommerce_product_class', [$this, 'getProductClass'], 10, 2);
+        add_filter('woocommerce_product_class', [$this, 'getProductClass'], 10, 4);
 
         // Add product data tabs
         add_filter('woocommerce_product_data_tabs', [$this, 'addProductDataTab']);
@@ -76,8 +76,13 @@ final class LicensedProductType
 
     /**
      * Get product class for licensed types
+     *
+     * @param string $className Default class name
+     * @param string $productType Product type
+     * @param string $postType Post type (usually 'product' or 'product_variation')
+     * @param int    $productId Product ID
      */
-    public function getProductClass(string $className, string $productType): string
+    public function getProductClass(string $className, string $productType, string $postType = '', int $productId = 0): string
     {
         if ($productType === 'licensed') {
             return LicensedProduct::class;
@@ -87,10 +92,21 @@ final class LicensedProductType
         }
         // Handle variations of licensed-variable products
         if ($productType === 'variation') {
-            // Check if parent is licensed-variable
-            global $post;
-            if ($post && $post->post_parent) {
-                $parentType = \WC_Product_Factory::get_product_type($post->post_parent);
+            // Get parent ID from the product post
+            $parentId = 0;
+            if ($productId > 0) {
+                $parentId = wp_get_post_parent_id($productId);
+            }
+            // Fallback to global $post if product ID not available
+            if (!$parentId) {
+                global $post;
+                if ($post && $post->post_parent) {
+                    $parentId = $post->post_parent;
+                }
+            }
+
+            if ($parentId) {
+                $parentType = \WC_Product_Factory::get_product_type($parentId);
                 if ($parentType === 'licensed-variable') {
                     return LicensedProductVariation::class;
                 }

src/Product/LicensedVariableProduct.php

@@ -50,11 +50,14 @@ class LicensedVariableProduct extends WC_Product_Variable
     }
 
     /**
-     * Licensed products are purchasable
+     * Licensed variable products are purchasable if the parent check passes
+     * Variable products don't have a direct price - their variations do
      */
     public function is_purchasable(): bool
     {
-        return $this->exists() && $this->get_price() !== '';
+        // Use the parent WC_Product_Variable logic
+        // which checks exists() and status, not price
+        return parent::is_purchasable();
     }
 
     /**