Update plugin README license to reference Snowflake Skills License

Author: iamontheinet

plugins/cortex-code/README.md

@@ -92,4 +92,6 @@ Skill discovery runs automatically on session start. To force a re-discovery, st
 
 ## License
 
-Copyright © 2026 Snowflake Inc. All rights reserved.
+Copyright (c) Snowflake Inc. All rights reserved.
+
+The skills in this project are licensed under the [Snowflake Skills License](../../LICENSE.md).