corpus_export_via_pandoc(): now produces a single output file (e.g. corpus.bib) as documented. Previously it passed the chunked CSL JSON directory to csljson_convert_pandoc(), which created a directory of per-chunk files at the output path, and it returned the wrong path when an extension had to be appended.
csljson_convert_pandoc(): the pdf_engine parameter is now respected. Previously --pdf-engine=xelatex was unconditionally appended, overriding any user-specified engine (e.g. "lualatex" or "pdflatex").
DOI extraction now delegates to openalexPro::extract_doi(), which fixes a regex that missed lowercase characters in DOI suffixes (e.g. 10.1234/abc-def).
Improvements
openalexPro declared as a formal dependency in DESCRIPTION (Imports).
rmarkdown moved from Suggests to Imports (it is used in exported functions).
Additional_repositories added to DESCRIPTION so CI and users can resolve openalexPro from r-universe automatically.
CI aligned with the rest of the openalexPro ecosystem: standard R-CMD-check.yaml (macOS, Windows, Ubuntu × devel/release/oldrel-1) and test-coverage.yaml added.