The LICENSE file only carried the short "how to apply" notice, not the
license itself, so it wasn't a valid GPLv3 distribution and license
detection tools couldn't identify it. Replace it with the canonical
674-line GNU GPL v3 text (sha256 8ceb4b9e...), and move the project
copyright line plus the "version 3 or any later version" grant into the
README, which now matches package.json's GPL-3.0-or-later.