Add rendered PDF (typst) for note v2

3-page A4 PDF with title/abstract/numbered sections/references —
the indexable artefact for Scholar/Zenodo. Rendered with typst
(installed at ~/dev/tools/document/typst).

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

Author: hyperpolymath