Implement version 0.0.8 features

- Remove Current Version field from product license settings
- Derive current version from latest product version in database
- Refactor email system to use WooCommerce email notification classes
- Add LicenseExpirationEmail WC_Email class for expiration warnings
- Add customizable email templates (HTML and plain text)
- Update settings to link to WooCommerce email configuration
- Update translations for new email-related strings

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

templates/emails/plain/license-expiration.php

@@ -0,0 +1,64 @@
+<?php
+/**
+ * License Expiration Warning Email (Plain Text)
+ *
+ * This template can be overridden by copying it to yourtheme/woocommerce/emails/plain/license-expiration.php.
+ *
+ * @package Jeremias\WcLicensedProduct\Templates\Emails
+ * @version 0.0.8
+ *
+ * @var \Jeremias\WcLicensedProduct\License\License $license
+ * @var int $days_remaining
+ * @var string $product_name
+ * @var string $expiration_date
+ * @var string $email_heading
+ * @var string $additional_content
+ * @var bool $sent_to_admin
+ * @var bool $plain_text
+ * @var \Jeremias\WcLicensedProduct\Email\LicenseExpirationEmail $email
+ */
+
+defined('ABSPATH') || exit;
+
+echo "=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=\n";
+echo esc_html(wp_strip_all_tags($email_heading));
+echo "\n=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=\n\n";
+
+$customer = get_userdata($license->getCustomerId());
+$customer_name = $customer ? $customer->display_name : __('Customer', 'wc-licensed-product');
+
+echo sprintf(esc_html__('Hello %s,', 'wc-licensed-product'), esc_html($customer_name)) . "\n\n";
+
+if ($days_remaining === 1) {
+    echo sprintf(
+        esc_html__('Your license for %s will expire tomorrow (%s).', 'wc-licensed-product'),
+        esc_html($product_name),
+        esc_html($expiration_date)
+    ) . "\n\n";
+} else {
+    echo sprintf(
+        esc_html__('Your license for %1$s will expire in %2$d days (%3$s).', 'wc-licensed-product'),
+        esc_html($product_name),
+        $days_remaining,
+        esc_html($expiration_date)
+    ) . "\n\n";
+}
+
+echo "----------\n";
+echo esc_html__('License Details', 'wc-licensed-product') . "\n";
+echo "----------\n\n";
+
+echo esc_html__('Product:', 'wc-licensed-product') . ' ' . esc_html($product_name) . "\n";
+echo esc_html__('License Key:', 'wc-licensed-product') . ' ' . esc_html($license->getLicenseKey()) . "\n";
+echo esc_html__('Domain:', 'wc-licensed-product') . ' ' . esc_html($license->getDomain()) . "\n";
+echo esc_html__('Expires:', 'wc-licensed-product') . ' ' . esc_html($expiration_date) . "\n\n";
+
+if ($additional_content) {
+    echo "----------\n\n";
+    echo esc_html(wp_strip_all_tags(wptexturize($additional_content)));
+    echo "\n\n";
+}
+
+echo esc_html__('View My Licenses', 'wc-licensed-product') . ': ' . esc_url(wc_get_account_endpoint_url('licenses')) . "\n\n";
+
+echo "=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=\n";