Both the MSI and the portable build were missing Applications\OpenCADStudio.exe\
DefaultIcon, causing a blank generic icon in the "Open with" context-menu list
and the "Choose another app" picker.
- packaging/windows/main.wxs: add Applications\OpenCADStudio.exe\DefaultIcon
(+ FriendlyAppName, shell\open\command, SupportedTypes) to the
DefaultPrograms component for MSI installs (HKLM).
- src/io/file_association.rs: add DefaultIcon to the Applications\
OpenCADStudio.exe block written at runtime for portable builds (HKCU).
https://claude.ai/code/session_01DFVSKgViFaxEjZD2KsTdtt
13eef50a00