feat: allow to highlight nodes from the spatial index

[seankmartin]

• fix: correct global bind key
• fix: allow seg ID to use display state
• feat: allow highlighting nodes from spatial index main changes are: 1. Cleaner repr of selected texture. Now stores a nodeID per vertex, instead of updating a 1D texture which effectively stores a bool of the highlihgted node. Then passes a uniform about the current node. 2. Removes now uneeded 1D texture update. 3. Cleans up some shader ternary ops to use mix. 4. Uses less GPU mem in overlay pass. As a note, this also would allow to do per node discarding which is something we discussed previously if ever really needed.