Wraps FPDFAnnot_GetLink plus the action/dest classification
helpers. Returns a single-row tibble with the same column shape as
pdf_page_links() (without the rect / quad_points geometry).
NULL if annot has no link entry.
Value
A 1-row tibble with action_type, uri, filepath,
dest_page, dest_view, dest_x, dest_y, dest_zoom. NULL
if the annotation has no link entry.
See also
pdf_page_links() for the page-wide enumeration.