Part Page Diagrams

[gklorfine]

The below summary was generated by Claude and then reviewed for accuracy. Note that it might be best to merge the GK-work6 PR (#57) before this one:

Summary

Adds DDAR-style "mind-map" bubble diagrams to the PDF edition: each part page (Parts I–IV) gets a diagram showing the part's chapters, and each chapter opener (Chapters 1–15) gets a diagram of its numbered sections, placed above the krantz chapter head. No book content changed — no .qmd or _quarto.yml edits; everything lives on the LaTeX/PDF side, and the HTML build is unaffected apart from the rebuild.

Diagram infrastructure (new)

• latex/diagrams/part1–4.tex and chap1–15.tex — TikZ sources for the 19 diagrams (hand-built bands/bubbles rather than the TikZ mindmap library, which produces hairline seam artifacts — rationale documented in issues/GK-part-pages.md)
• latex/diagrams/diagram-common.tex — shared styles (\band macro, root/satellite bubble styles)
• latex/diagrams/make-diagrams.sh — compiles the sources with xelatex into figs/diagrams/*.pdf
• figs/diagrams/*.pdf — the 19 pre-built diagram PDFs the book actually includes
• issues/make-part-diagrams.py — one-off generator that produced the initial .tex sources

Preamble integration

• latex/preamble.tex — two new \pretocmd hooks: one on \@endpart (part diagram below the part title, keyed by the existing partnum counter) and one on \@makechapterhead (chapter diagram top-right, keyed by \thechapter). Both are wrapped in \IfFileExists, so the End Matter part and front matter render unchanged.
• latex/part-colors.tex (new) — part accent colors moved out of preamble.tex into one file \input by both the preamble and the diagram sources, so retheming happens in one place.

Build script (macOS fixes)

• build.sh — adds TinyTeX//Library/TeX/texbin to PATH when makeindex isn't found, and switches sed -i to sed -i.bak so the index-normalization step works with both BSD and GNU sed.

Docs / housekeeping

• issues/GK-part-pages.md — full write-up of the design, hooks, and gotchas (e.g., diagram filenames must not be zero-padded)
• memory/ notes for the diagram and color work; typo fix in the Chapter 13 diagram ("Levene test" → "Levene's test" in bubble 13.9)

Rebuilt output (bulk of the diff)

• docs/ HTML, index.pdf / pdf/Vis-MLM.pdf, Vis-MLM.tex, index/aux files, and figs/ PNGs/PDFs — regenerated by an all-formats rebuild on macOS after merging master (PNGs grew ~4–6× from the retina-resolution rebuild; no content changes)

Note for reviewers

~610 of the 664 changed files are regenerated output (docs/, figs/, pdf/, TeX aux files). The real change is 34 source files plus the 19 pre-built diagram PDFs in figs/diagrams/.