13 Documenting the package and adding README and pkgdown website

At build time we generate the package’s reference documentation, README, and pkgdown website: litr::document() writes the man/ pages and NAMESPACE; the README is rendered from source-files/README.Rmd (its two figures copied into man/figures/); the CITATION file is installed so citation("cssr") and the pkgdown “Citation” page cite the paper (arXiv:2201.00494); NEWS.md is copied to the package root from source-files/NEWS.md, where it is edited, so that news(package = "cssr") and the pkgdown “Changelog” page both have it (it must be copied before litr::add_pkgdown() runs below, since that is what builds the changelog page); and the WORDLIST file is installed alongside CITATION so that devtools::spell_check() accepts this package’s domain vocabulary and flags only genuine misspellings. Its entries fall into a few groups: author surnames and the journals that published them; package, function, and argument names; data-frame column names; fragments of underscore-separated identifiers, which appear because the spell checker splits tokens at underscores (so X_train_selec contributes selec, and clus_sel_mat contributes clus and sel — these are documented argument and slot names, not truncations); a few mathematical and typographic tokens from the README’s LaTeX; the R color literals grey and steelblue, which are spellings fixed by R’s own palette rather than by us and so are quoted verbatim from default argument values; and a handful of ordinary English words the en_US dictionary happens to lack. Everything else is treated as a typo and fixed at the source; the Exploring results, Prediction, and Advanced usage vignettes are added from source-files/ via litr::add_vignettes(); and litr::add_pkgdown() builds the site (including the vignettes under Articles).