I noticed that pages and posts that are marked private do not show up in the page and post list. How could I add code blocks to header/footer of these pages?
Sorry for the delay in getting back to you.
Unfortunately the CJT plugin does not show Private page at present, but this would certainly be a good idea to develop in the near future.
In fact, there has been a number of other users who have also requested Private and Draft Pages and Posts to show in the Assignment Panel.