feat: add auto-release sales order option

PATCH salesOrders status to 'Released' after creation and line items.
Controlled by Auto-Release Order checkbox in Order Settings.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

woo-business-central/admin/class-wbc-admin.php

@@ -97,6 +97,9 @@ class WBC_Admin {
         register_setting( 'wbc_orders', 'wbc_default_customer_number', array(
             'sanitize_callback' => 'sanitize_text_field',
         ) );
+        register_setting( 'wbc_orders', 'wbc_auto_release_order', array(
+            'sanitize_callback' => array( $this, 'sanitize_checkbox' ),
+        ) );
     }
 
     /**