Modular LaTeX CV: scaffolding, 13 chapters, altacv styling

Replace the monolithic ODT with a modular LaTeX source tree that becomes
the canonical full CV:

- preamble.tex: altacv color/font overrides + compact-row macros
  (\cvrow, \cvgrant, \cvtalk, \cvalum, \cvpub) so dense lists keep
  baseline-aligned dates without the tabularx misalignment the
  custom v1 had.
- cv-full.tex: driver including the 13 chapters in order.
- chapters/*.tex: header, positions, education, grants, teaching,
  examinations, service, talks, collaborators, alumni, publications,
  products (solo-founded flyRoom + Berengar), software.
- tex-vendor/altacv.cls (v1.7.4): vendored, not in TeX Live.
- Makefile: dockerised xelatex build via texlive/texlive:latest,
  with TEXINPUTS=.:./tex-vendor: so the vendored class resolves.

Output: 6-page build/cv-full.pdf (down from 10 in the first pass).

.gitignore

@@ -4,3 +4,17 @@
 # Backup / autosave
 *.bak
 .~*
+
+# LaTeX build artefacts
+build/
+*.aux
+*.log
+*.out
+*.toc
+*.fls
+*.fdb_latexmk
+*.synctex.gz
+*.xdv
+
+# Claude Code session state
+.claude/