I should be able to define a "Master Page" template for my Space

Summary: That is, my Space should be able to define a framing template, with menus, headers, footers, etc, that is consistent across the Space, and all Things should fit their content into it.

This is the way many web-design systems work, because it's just plain useful. We should have something similar.

Ideally, this should work in the usual way, where it can be defined at the Space, Model or Thing level. But Space is by far the most important.

This should not allow you to obscure the Querki header or footer bars -- those are system tech, and for reasons of both users expectations and security must always be visible.