fix(licence): clear scaffold-placeholder leak (rebuilt clean) (#17)

Rebuilt from origin/main (original #12 was behind + conflicting).
PLMP/PMLP + doubled -> PMPL-1.0-or-later. Diff = SPDX lines only.
Refs hyperpolymath/standards LICENCE-POLICY.adoc A5.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath