Refactor email to use WooCommerce transactional email system

- Remove legacy email template files
- Use WooCommerce's email-header.php and email-footer.php templates
- Render email content inline for consistent WooCommerce styling
- Remove template location filter from LicenseEmailController

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

src/Email/LicenseEmailController.php

@@ -44,9 +44,6 @@ final class LicenseEmailController
 
         // Cron action for checking expiring licenses
         add_action('wclp_check_expiring_licenses', [$this, 'sendExpirationWarnings']);
-
-        // Add email templates location for theme overrides
-        add_filter('woocommerce_locate_template', [$this, 'locateTemplate'], 10, 3);
     }
 
     /**
@@ -61,30 +58,6 @@ final class LicenseEmailController
         return $email_classes;
     }
 
-    /**
-     * Locate templates in plugin directory
-     *
-     * @param string $template Template path
-     * @param string $template_name Template name
-     * @param string $template_path Template path prefix
-     * @return string Modified template path
-     */
-    public function locateTemplate(string $template, string $template_name, string $template_path): string
-    {
-        // Only handle our email templates
-        if (strpos($template_name, 'emails/license-') !== 0) {
-            return $template;
-        }
-
-        $plugin_template = WC_LICENSED_PRODUCT_PLUGIN_DIR . 'templates/' . $template_name;
-
-        if (file_exists($plugin_template)) {
-            return $plugin_template;
-        }
-
-        return $template;
-    }
-
     /**
      * Schedule the expiration check cron job
      */