Entities_determined_by_user is an awkward component.

It shouldn't show up in the user-facing Archetype (obviously if a user is building the archetype it's user-edited) and the need to manually set it on edits is fragile.

Proposal: instead track a hash of (SpaceViewClass, Query) for all space-views that have ever been added via the heuristics.

If it's ever been added, we never need to add it again automatically.