[idea] Hierachical space groups

[kunchenguid]

idea / problem

I use Herdr to supervise a tree of coding-agent runtimes: one primary supervisor plus several persistent second-level supervisors, and every worker agent runs in its own space. The space list is flat, so it cannot show that ownership tree.

I currently approximate the hierarchy by manually reordering spaces so each supervisor's fleet stays contiguous, but that arrangement is fragile as spaces appear, disappear, or are restored, and adjacency still does not communicate parent/child ownership.

requested change

I'd like Herdr to support parent/child space grouping, collapsible groups, and stable ordering of the hierarchy. The need is to express and navigate the existing relationship directly rather than approximate it through adjacency in one flat list.

why you want this

This would make a multi-supervisor fleet legible at a glance, let me collapse supervisors I am not actively watching, and keep related spaces together as the fleet changes. It would reduce manual list maintenance and make the UI reflect the actual operational ownership of each space.