forked from 1b-agent/opencadstudio-upstream
Implements a full in-app file browser window for Save As, replacing the rfd dialog that could not expose the selected filter index on Linux. The new chooser includes directory navigation, a scrollable file list, filename input, and a format drop-down (DWG/DXF × 2018/2013/2010/2007/2004/2000/R14). Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>