The Export dialog's GIF choice runs through SlideApp::export_as (desktop and web download),
.gif is a writable output extension for convert/run, and the CLI help pages describe GIF output
and --export-params. A file.export `slides` range string ("1-3,5") works for GIF as for PDF.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
convert, run --save and run --export picked the format from the output
extension and fell back to native .deckcraft bytes for any extension
they didn't know, so out.odp, out.gif, out.svg and out.outline were
zips with exit status 0. They now fail before writing anything, with
the extension and the supported ones in the error.
