Replace the face/back boolean with a three-state facing (face, back,
standing) seeded from setup placements. Parts now orient about the
anchor at the resting face/edge, so back-down parts sit on the table
instead of below it and standing parts rest on their bottom edge.
Replace the path->part-list store with a per-part map keyed by part id, so each placed part carries its path, stack index, and face. Derive each path's ordered children for stacking, and flip face-down parts in PartPlacement.
Replace the dark surface plane with a grey background and a spotlight,
size the contact shadow to the table, and scale its blur and fade with
the shadow plane. Disable depth test on the stacking curve overlay.
Add a toggleable surface plane, bounds outline, and constant-size HTML
label. Scale placement and mount anchors to world units so parts land on
the surface, and rotate parts to face up.
Wire the tabletop library into the setup detail route: seed the store
from the setup, resolve the surface mount tree, and render world and HUD
surfaces. Add serializedToPackage to convert the vite-emitted package.
Implement the tabletop library's game state store, setup seeding with
bare-type expansion, surface mount tree resolution, part placement, and
the stacking positioning process with a dependency-free SVG path helper.
Wire the public API and add unit plus vite integration tests.