feat: add Quarto themes and templates (revealjs, HTML, PDF, Typst)

Integrate Civilytics Reveal.js slide extension, HTML/PDF/Typst document
themes, and _brand.yml into the package under inst/quarto/. Three new
helper functions (use_civilytics_revealjs, use_civilytics_theme,
use_civilytics_brand) copy assets into a user's Quarto project. Logos
are stored once in inst/img/ and distributed at install time.

inst/quarto/latex/civilytics.tex

@@ -0,0 +1,112 @@
+% =============================================================
+% Civilytics — LaTeX preamble for Quarto PDF
+% Usage in YAML:
+%   format:
+%     pdf:
+%       include-in-header: quarto/latex/civilytics.tex
+%       include-before-body: quarto/latex/civilytics-title.tex
+% Requires: xelatex or lualatex (for system fonts).
+% =============================================================
+
+\usepackage{xcolor}
+\usepackage{fontspec}
+\usepackage{titlesec}
+\usepackage{titling}
+\usepackage{fancyhdr}
+\usepackage{enumitem}
+\usepackage{booktabs}
+\usepackage{caption}
+\usepackage[hidelinks]{hyperref}
+\usepackage{microtype}
+\usepackage{tcolorbox}
+\tcbuselibrary{skins,breakable}
+
+% --- Civilytics palette ---
+\definecolor{paper}{HTML}{FAF7F2}
+\definecolor{paper2}{HTML}{F2EDE4}
+\definecolor{ink}{HTML}{0E1A2B}
+\definecolor{ink2}{HTML}{2B3A52}
+\definecolor{ink3}{HTML}{5A6A82}
+\definecolor{rule}{HTML}{D6CEBD}
+\definecolor{ruleStrong}{HTML}{B8AE97}
+\definecolor{navy}{HTML}{22406A}
+\definecolor{ember}{HTML}{C25311}
+\definecolor{emberDark}{HTML}{923D00}
+\definecolor{teal}{HTML}{1F6F70}
+\definecolor{plum}{HTML}{6B3A5E}
+
+% --- Page color ---
+\pagecolor{paper}
+\color{ink}
+
+% --- Fonts (require local install or fontspec lookup) ---
+\setmainfont{Source Serif 4}[
+  UprightFont = *,
+  ItalicFont = * Italic,
+  BoldFont = * SemiBold,
+  BoldItalicFont = * SemiBold Italic,
+  Ligatures = TeX,
+]
+\setsansfont{Inter}[Ligatures = TeX]
+\setmonofont{JetBrains Mono}[Scale = 0.92]
+\newfontfamily\displayfont{Libre Franklin}[Ligatures = TeX]
+
+% --- Hyperlinks ---
+\hypersetup{
+  colorlinks = true,
+  linkcolor  = navy,
+  urlcolor   = navy,
+  citecolor  = navy,
+  filecolor  = navy,
+}
+
+% --- Section headings ---
+\titleformat{\section}[block]
+  {\bfseries\Large\displayfont\color{ink}}
+  {}{0pt}
+  {\titlerule[0.4pt]\vspace{4pt}}[\vspace{-6pt}]
+\titleformat{\subsection}[block]
+  {\bfseries\large\displayfont\color{ink}}{}{0pt}{}
+\titleformat{\subsubsection}[block]
+  {\bfseries\normalsize\displayfont\color{ink}}{}{0pt}{}
+
+% --- Page header / footer ---
+\pagestyle{fancy}
+\fancyhf{}
+\renewcommand{\headrulewidth}{0pt}
+\renewcommand{\footrulewidth}{0pt}
+\fancyhead[L]{\sffamily\scriptsize\color{ink3}\MakeUppercase{Civilytics Consulting}}
+\fancyhead[R]{\sffamily\scriptsize\color{ink3}\thetitle}
+\fancyfoot[L]{\sffamily\scriptsize\color{ink3}civilytics.consulting}
+\fancyfoot[C]{\sffamily\scriptsize\color{ink3}\thepage}
+\fancyfoot[R]{\sffamily\scriptsize\color{ink3}\textcopyright\ 2026}
+
+% --- Captions ---
+\captionsetup{
+  font={sf,small,color=ink3},
+  labelfont={sf,bf,color=ink3},
+  labelsep=period,
+  justification=raggedright,
+  singlelinecheck=false,
+}
+
+% --- Pullquote ---
+\newtcolorbox{pullquote}{
+  enhanced, breakable, frame hidden, colback=paper,
+  borderline west = {2pt}{0pt}{ember},
+  left=14pt, right=4pt, top=4pt, bottom=4pt,
+  fontupper={\itshape\rmfamily\large\color{ink}},
+}
+
+% --- Code blocks (Pandoc + listings or minted both inherit colors below) ---
+\definecolor{codebg}{HTML}{0E1A2B}
+\definecolor{codefg}{HTML}{FAF7F2}
+
+% --- Lists tighter ---
+\setlist{itemsep=2pt, topsep=4pt}
+
+% --- Tabular numerals ---
+\newcommand{\tnum}[1]{{\addfontfeature{Numbers={Tabular,Lining}}#1}}
+
+% --- Ember accent rule above section starts ---
+\newcommand{\emberrule}{{\color{ember}\rule{60pt}{3pt}}\par\vspace{4pt}}