v1.4.13 — Replace proprietary fonts with free, portable equivalents
preamble.tex required Consolas (monospace) and Palatino Linotype
(serif), both proprietary Microsoft fonts. On any machine without them
installed, fontspec silently fell back to nullfont for text using
those families — every code listing rendered as invisible/missing
glyphs — and xelatex eventually crashed trying a legacy bitmap-font
fallback for Consolas specifically. Replaced with DejaVu Sans Mono and
TeX Gyre Pagella (a metric-compatible Palatino clone), both free and
bundled with any standard TeX Live install. Verified with a from-
scratch rebuild: zero missing-character warnings and zero errors
across all three xelatex passes, versus 100+ errors and a crash
before. Also synced latex/references.bib (a separate bibliography
database from bibliography.md, kept manually in sync) with this
session’s earlier citation fixes — it had fallen out of sync.