The install script was being copied into every new letter directory
it created. Delete it after unpacking so new letter directories only
contain the template itself.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Add new_tex_uwletter script (moved from ~/bin) with bug fixes: set -e,
quoted variables, WORK_DIR instead of TMPDIR, existence check for
destination, and mktemp inside the conditional. Update README to fix
stale URLs, ShareLaTeX -> Overleaf, MacOSX -> macOS, typo in
Dasgupta's email, and add script usage section.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
