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.

man/dot-copy_logos.Rd

@@ -0,0 +1,27 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/quarto.R
+\name{.copy_logos}
+\alias{.copy_logos}
+\title{Copy logo SVGs from inst/img/ to a target directory}
+\usage{
+.copy_logos(
+  dest_dir,
+  path,
+  force,
+  files = c("civilytics-mark.svg", "civilytics-mark-reverse.svg",
+    "civilytics-wordmark.svg", "civilytics-wordmark-reverse.svg", "civilytics-pulse.svg")
+)
+}
+\arguments{
+\item{dest_dir}{Destination directory relative to `path`.}
+
+\item{path}{Project root.}
+
+\item{force}{Overwrite existing files?}
+
+\item{files}{Character vector of logo filenames to copy.}
+}
+\description{
+Copy logo SVGs from inst/img/ to a target directory
+}
+\keyword{internal}