[andreasvc]

Solution: you anonymize the link for peer-review, and only include the real link in the final version. This way the code is not peer-reviewed of course, but peer review can look at the pseudo-code given in the paper.

Your last point really has nothing to do with given away code, nor with peer review: you can plagiarize just about anything. This generally doesn't happen because scientists care a lot about giving credit and recognizing priority.