The top bar becomes a steel gantry. Its centre window is a mask cut-out the
3D exit sign docks into; between signs the window shows the dash read-out.
The drive controls move into the right bay, and the reading viewport is
clipped at the beam, so the empty band under the bar is gone.
Exercise sign state updates and composition together, covering responsive placement, grounding, label reuse, resource ownership, and departure motion. Update poster and visual-model expectations while retaining behavioral checks.
Validation: 46 focused tests passed before commit. The preceding full build:preview run passed all 673 tests plus typecheck, builds, prerender, artifact verification, and transfer budgets.
