paper_template (knitr): port to master's article + lualatex stack

Bring the knitr paper template up to date with the typography work
on master. The preamble now mirrors master's paper_template/text.tex:

- \DocumentMetadata{pdfstandard=ua-2} + tagpdf instead of the old
  memoir / pdfmanagement-only setup
- article class with cdsc-paper.sty (the article-class replacement
  for cdsc-memoir.sty added on master)
- fontspec with EB Garamond and TeX Gyre Heros, plus
  \defaultfontfeatures{Ligatures=TeX} so --, ---, ``, '' work
- Makefile builds with latexmk -lualatex instead of -pdf

The knitr-specific bits are preserved unchanged:

- <<init>>= chunk for knit_hooks and resources/preamble.R
- <<test_table>>= chunk demonstrating kable inside a table float
- %.tex: %.Rtex pattern rule for knit() in the Makefile

verapdf --flavour ua2: 0 failures, 1723 passed rules.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

paper_template/cdsc-paper.sty

@@ -0,0 +1,110 @@
+% Article-class styles and page layout for CDSC paper documents.
+%
+% This file replaces the older cdsc-memoir.sty. It targets the
+% standard `article' class so the LaTeX tagging-project can produce
+% tagged, accessible PDFs --- memoir is currently incompatible with
+% that work. The look-and-feel is kept as close to the previous
+% cdsc-article chapterstyle as is practical.
+%
+% Copyright 2009-2026 Benjamin Mako Hill <mako@atdot.cc>
+% Copyright 2008-2009 Kieran Healy <kjhealy@soc.duke.edu>
+
+% Distributed as free software under the GNU GPL v3
+
+\usepackage{lastpage}
+\usepackage{datetime}
+\usepackage{xcolor}
+
+%%% Page styles (replaces memoir's \makepagestyle / \makeevenhead etc.)
+\usepackage{fancyhdr}
+\setlength{\headheight}{14.5pt}
+\addtolength{\topmargin}{-2.5pt}
+
+% Basic: page number in small caps in the upper-right corner
+\fancypagestyle{cdsc-page}{%
+  \fancyhf{}%
+  \fancyhead[R]{\scshape\thepage}%
+  \renewcommand{\headrulewidth}{0pt}%
+}
+
+% Variant with git revision info in the footer (requires the vc package).
+\fancypagestyle{cdsc-page-git}{%
+  \fancyhf{}%
+  \fancyhead[R]{\scshape\thepage}%
+  \fancyfoot[C]{\texttt{\footnotesize\textcolor{BrickRed}{git revision \VCRevision\ on \VCDateTEX}}}%
+  \renewcommand{\headrulewidth}{0pt}%
+}
+
+% Variant with a build timestamp in the footer (useful on Overleaf/etc.)
+\fancypagestyle{cdsc-page-overleaf}{%
+  \fancyhf{}%
+  \fancyhead[R]{\scshape\thepage}%
+  \fancyfoot[C]{\texttt{\footnotesize\textcolor{BrickRed}{Buildstamp/Version:~\today}}}%
+  \renewcommand{\headrulewidth}{0pt}%
+}
+
+\pagestyle{cdsc-page}
+
+%%% Section heading styles (replaces memoir's \setsecheadstyle etc.)
+\usepackage{titlesec}
+
+% Sections: large small caps; period after the number
+\titleformat{\section}
+  {\large\scshape}{\thesection.}{0.5em}{}
+\titlespacing*{\section}{0pt}{*2}{1.7ex}
+
+% Subsections: italic
+\titleformat{\subsection}
+  {\normalsize\itshape}{\thesubsection.}{0.5em}{}
+
+% Subsubsections: small bold, runin (matches memoir's negative skip behavior)
+\titleformat{\subsubsection}[runin]
+  {\small\bfseries}{\thesubsubsection.}{0.5em}{}[\hskip 0.5em]
+
+% By default, suppress numbering at the section level (matches the
+% memoir template's default of \setsecnumdepth{chapter}). To enable
+% numbered sections and subsections, comment the line below and
+% uncomment the alternative.
+\setcounter{secnumdepth}{0}
+% \setcounter{secnumdepth}{2}
+
+%%% Title block (titling package replaces memoir's title hooks)
+\usepackage{titling}
+
+% Title flush left, italic, large
+\pretitle{\flushleft\LARGE\itshape}
+\posttitle{\par\vskip 0.5em}
+\preauthor{\flushleft\large\lineskip 1em}
+\postauthor{\par\lineskip 1em}
+\predate{\flushleft\footnotesize\vspace{0.65em}}
+\postdate{\par\vskip 1em}
+
+%% \published{...}: a note about the publication status, printed in
+%% small type at the very top of the title block. Use this for
+%% draft/working-paper notices.
+\newcommand{\puB}{}
+\newcommand{\published}[1]{\gdef\puB{#1}}
+\renewcommand{\maketitlehooka}{\par\noindent\footnotesize\puB}
+
+%%% Abstract: runin style ("**Abstract:** the quick brown fox..."),
+%%% indented from both margins (via the quote environment, which gives
+%%% the side indent without adding first-line paragraph indentation).
+\renewenvironment{abstract}%
+  {\par\addvspace{\medskipamount}\small
+   \begin{quote}\noindent\textbf{Abstract:}\hspace{0.5em}\ignorespaces}%
+  {\end{quote}\par\medskip}
+
+%%% List spacing (replaces memoir's \firmlists --- tighter lists)
+\usepackage{enumitem}
+\setlist{topsep=0pt, partopsep=0pt}
+
+%%% Caption font
+\usepackage{caption}
+\captionsetup{font=small}
+
+%%% Footnote symbol command (for \thanks{} footnotes that should not
+%%% have a numeric mark). Use as \symbolfootnote[0]{Footnote text}.
+\long\def\symbolfootnote[#1]#2{\begingroup%
+  \def\thefootnote{\fnsymbol{footnote}}\footnote[#1]{#2}\endgroup}
+
+\endinput