How to 'fix' a twisted hidden door?
I'm hoping Solar Mike's solution works and solves your problem but that's a lot of twisting to correct by &quot;pushing&quot; and seems like it would be likely to revert back to the way it was built.
You're new at woodworking and your job looks pretty good, except for the gap. I don't thing a spacer will give you the desired effect you're looking for, especially for a secret door. Bite the bullet and fix it right, your option #3. If you don't, it will probably bug you every time you look at it and you will eventually end up fixing it right. We've all been there, done that. The more you try to cover up a mistake, the worse it looks. Just my humble opinion.