Improve selection system to select child components / elements of top level elements in a scene

[itsdouges]

Rough idea of the behaviour:

• clicking anything in left panel directly selects the object in the scene
• single clicking an object in the scene would select objects in the current level
• double clicking would go down a level and select the child
• How would we articulate current level in the UI?
• need to explore what UX is familiar here, check out Figma / Spline for inspiration

Technical notes:

• the current system relies on the global set path and exportName. We can bring those into state and then update the logic to handle it being dynamically set. Those values would be used to filter valid selections.
• this feature might make sense to work on after refactoring the selection system off groups (issue: ?)