- Validate cwd is non-empty in shell:open-in-editor IPC handler
- Check shell.openPath() return value and throw on error
- Attach spawn error listener to prevent crashes from missing CLI
- Validate localStorage lastEditor against known EDITORS list
- Only call preventDefault() for Cmd+O when action will run

Co-authored-by: Julius Marminge <juliusmarminge@users.noreply.github.com>