I spent nearly two days 
figuring this out, and I finally managed to get Claude Code installed on Windows and integrated into Cursor!
In my case, even after successfully installing both Cursor and Claude Code, the /ide route still couldn’t detect Cursor — I tried all the usual solutions (adding to PATH, manually dragging the .vsix file, etc.) but nothing worked.
Eventually, I discovered the trick: you need to launch Cursor from a WSL terminal. Just open your WSL terminal and type cursor to start it. Make sure you navigate to your project folder inside the WSL environment (note that Windows files show up under /mnt/...), and open the project from there.
You don’t need to copy your entire project into WSL — just launching Cursor this way makes it work!
That said, this solution assumes you’ve already tried the basic setup steps mentioned earlier. If you skip those and jump straight to launching via WSL, it might still not work 
Hope this helps someone out there! 