Replace the individual new_knitr_document, new_tex_assignment, and
new_tex_letter scripts with a single new_tex_document script that takes
a document type as its first argument. Fix bugs present in all scripts:
unquoted variables, TMPDIR name collision, missing existence checks, and
mktemp running unconditionally. Add cdsc_tex_aliases.sh for backwards
compatibility with old script names. Add rename_tex_to_dirname script
(moved from ~/bin). Update README and wiki page to reflect new setup.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
