Confirm repository-wide license with copyright holders #4

This repository does not currently have a confirmed repository-wide license in the migration audit. Please have a copyright holder or authorized maintainer confirm the intended SPDX license and identify any vendored subtrees with separate terms before adding a root LICENSE file. Do not infer a license from dependency headers, paper access terms, or neighboring repositories.

Acceptance criteria:

• authorized maintainer records the intended license;
• third-party/vendored exceptions are documented;
• root LICENSE and README license section agree;
• GitHub detects the resulting license.