Add projection-multi targets for Haskell's `stack` build system

This pull request improves the support for Haskell's `stack` build system by doing two things: 1. Not showing `cabal` targets when `stack` targets are available (this looks like it was a bug in the existing code). 2. Adding compile-multi targets by parsing the packages and targets that `stack` knows about. Example targets: <img width="1208" height="1092" alt="Ekrankopio de 2025-09-21 06-46-35" src="https://github.com/user-attachments/assets/a3d31b71-7407-40a6-ad15-a58b6608b32a" /> Please see the commit messages for more details