Faithful data-driven visual filter when the render model carries no matching domain identity

A design spec promised "clicking a root-cause chip filters the 3D lattice to that root cause." But the lattice nodes (an R3F InstancedMesh of ~240 icosahedra) carry only geometry (position, radius, BFS depth, overshoot flag) and NO domain identity: there is no root_cause or record field on a node. The only record-to-node link is a deterministic FNV hash used to place a single anchor. So a literal "filter nodes whose root_cause === slug" is impossible; the data to filter on does not exist on the render model. Faking per-node identity would be dishonest and arbitrary.