You cannot prevent yourself from restoring a production database at any point in the future by any other method then double-checking your work before you hit the button.

Sysadmin will ALWAYS be able to restore. If you don't want that ability, take away Sysadmin and give yourself other server roles except for the Backup role.

Think of it this way. To SQL Server, a sysadmin is God. Therefore there is nothing you can do to prevent God from doing whatever (s)he likes.

You should be proud of yourself. You have just taught yourself a valuable lesson that will stay with you the rest of your career. If I understand the situation correctly, you only had to teach it to yourself once. Some people make the same mistakes over and over again without learning from them.