chore: relicense MIT -> GPL-2.0-or-later ahead of GPL code merge (see NOTICE.md)

advanced-mcp-plugin.php

@@ -8,8 +8,13 @@
  * Requires PHP:      8.0
  * Author:            AskTam
  * Author URI:        https://asktam.net
- * License:           MIT
+ * License:           GPL-2.0-or-later
+ * License URI:       https://www.gnu.org/licenses/gpl-2.0.html
  * Text Domain:       advanced-mcp-plugin
+ *
+ * Relicensed from MIT to GPL-2.0-or-later on 2026-10-15 because this plugin now
+ * incorporates and adapts GPL-2.0 code. See NOTICE.md for upstream sources and
+ * attributions (GPL §2a: modified files are marked and original notices preserved).
  */
 
 defined('ABSPATH') || exit;