Add licensed variable product support for duration-based licenses (v0.5.3)

Customers can now purchase licenses with different durations (monthly,
yearly, lifetime) through WooCommerce product variations. Each variation
can have its own license validity settings.

New features:
- LicensedVariableProduct class for variable licensed products
- LicensedProductVariation class for individual variations
- Per-variation license duration and max activations settings
- Duration labels in checkout (Monthly, Quarterly, Yearly, etc.)
- Full support for WooCommerce Blocks checkout with variations
- Updated translations for German (de_CH)

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

src/Product/LicensedProductVariation.php

@@ -0,0 +1,196 @@
+<?php
+/**
+ * Licensed Product Variation Class
+ *
+ * @package Jeremias\WcLicensedProduct\Product
+ */
+
+declare(strict_types=1);
+
+namespace Jeremias\WcLicensedProduct\Product;
+
+use Jeremias\WcLicensedProduct\Admin\SettingsController;
+use WC_Product_Variation;
+
+/**
+ * Licensed Product Variation type extending WooCommerce Product Variation
+ *
+ * Each variation can have its own license duration settings.
+ */
+class LicensedProductVariation extends WC_Product_Variation
+{
+    /**
+     * Constructor
+     */
+    public function __construct($product = 0)
+    {
+        parent::__construct($product);
+    }
+
+    /**
+     * Licensed products are always virtual
+     */
+    public function is_virtual(): bool
+    {
+        return true;
+    }
+
+    /**
+     * Get max activations for this variation
+     * Falls back to parent product, then to default settings
+     */
+    public function get_max_activations(): int
+    {
+        // Check variation-specific setting first
+        $value = $this->get_meta('_licensed_max_activations', true);
+        if ($value !== '' && $value !== null) {
+            return max(1, (int) $value);
+        }
+
+        // Fall back to parent product
+        $parent = wc_get_product($this->get_parent_id());
+        if ($parent && method_exists($parent, 'get_max_activations')) {
+            return $parent->get_max_activations();
+        }
+
+        return SettingsController::getDefaultMaxActivations();
+    }
+
+    /**
+     * Check if variation has custom max activations set
+     */
+    public function has_custom_max_activations(): bool
+    {
+        $value = $this->get_meta('_licensed_max_activations', true);
+        return $value !== '' && $value !== null;
+    }
+
+    /**
+     * Get validity days for this variation
+     * This is the primary license setting that varies per variation
+     * Falls back to parent product, then to default settings
+     */
+    public function get_validity_days(): ?int
+    {
+        // Check variation-specific setting first
+        $value = $this->get_meta('_licensed_validity_days', true);
+        if ($value !== '' && $value !== null) {
+            $days = (int) $value;
+            // 0 means lifetime
+            return $days > 0 ? $days : null;
+        }
+
+        // Fall back to parent product
+        $parent = wc_get_product($this->get_parent_id());
+        if ($parent && method_exists($parent, 'get_validity_days')) {
+            return $parent->get_validity_days();
+        }
+
+        return SettingsController::getDefaultValidityDays();
+    }
+
+    /**
+     * Check if variation has custom validity days set
+     */
+    public function has_custom_validity_days(): bool
+    {
+        $value = $this->get_meta('_licensed_validity_days', true);
+        return $value !== '' && $value !== null;
+    }
+
+    /**
+     * Check if license should be bound to major version
+     * Falls back to parent product, then to default settings
+     */
+    public function is_bound_to_version(): bool
+    {
+        // Check variation-specific setting first
+        $value = $this->get_meta('_licensed_bind_to_version', true);
+        if ($value !== '' && $value !== null) {
+            return $value === 'yes';
+        }
+
+        // Fall back to parent product
+        $parent = wc_get_product($this->get_parent_id());
+        if ($parent && method_exists($parent, 'is_bound_to_version')) {
+            return $parent->is_bound_to_version();
+        }
+
+        return SettingsController::getDefaultBindToVersion();
+    }
+
+    /**
+     * Check if variation has custom bind to version setting
+     */
+    public function has_custom_bind_to_version(): bool
+    {
+        $value = $this->get_meta('_licensed_bind_to_version', true);
+        return $value !== '' && $value !== null;
+    }
+
+    /**
+     * Get the license duration label for display
+     */
+    public function get_license_duration_label(): string
+    {
+        $days = $this->get_validity_days();
+
+        if ($days === null) {
+            return __('Lifetime', 'wc-licensed-product');
+        }
+
+        if ($days === 30) {
+            return __('Monthly', 'wc-licensed-product');
+        }
+
+        if ($days === 90) {
+            return __('Quarterly', 'wc-licensed-product');
+        }
+
+        if ($days === 365) {
+            return __('Yearly', 'wc-licensed-product');
+        }
+
+        return sprintf(
+            /* translators: %d: number of days */
+            _n('%d day', '%d days', $days, 'wc-licensed-product'),
+            $days
+        );
+    }
+
+    /**
+     * Get current software version from parent product
+     */
+    public function get_current_version(): string
+    {
+        $parent = wc_get_product($this->get_parent_id());
+        if ($parent && method_exists($parent, 'get_current_version')) {
+            return $parent->get_current_version();
+        }
+
+        $versionManager = new VersionManager();
+        $latestVersion = $versionManager->getLatestVersion($this->get_parent_id());
+
+        return $latestVersion ? $latestVersion->getVersion() : '';
+    }
+
+    /**
+     * Get major version number from parent product
+     */
+    public function get_major_version(): int
+    {
+        $parent = wc_get_product($this->get_parent_id());
+        if ($parent && method_exists($parent, 'get_major_version')) {
+            return $parent->get_major_version();
+        }
+
+        $versionManager = new VersionManager();
+        $latestVersion = $versionManager->getLatestVersion($this->get_parent_id());
+
+        if ($latestVersion) {
+            return $latestVersion->getMajorVersion();
+        }
+
+        return 1;
+    }
+}