fix(tabletop): tilt cards uniformly about the y axis

Apply the same tilt to every stacked part and rotate it about its local
Y axis instead of Z. Default tilt to 1 degree when a stacking strategy
is present, and arc the poker deck along the surface's bottom edge.

packages/tabletop/src/placement.tsx

@@ -21,7 +21,7 @@ export function PartPlacement({ pkg, placement }: { pkg: Package; placement: Pla
 
   // Route anchors and stacking offsets are in mm; convert to world units so
   // parts land on the (world-scaled) surface. `z` raises the part along the
-  // surface normal (world +Y); `tilt` fans it about its local Y (long) axis.
+  // surface normal (world +Y); `tilt` rotates it about its local Y (long) axis.
   // Angles are authored in degrees; three.js expects radians.
   const anchorX = ((candidate?.x ?? route.x ?? 0) + x) * MM_TO_WORLD;
   const anchorY = ((candidate?.y ?? route.y ?? 0) + y) * MM_TO_WORLD;
@@ -31,7 +31,7 @@ export function PartPlacement({ pkg, placement }: { pkg: Package; placement: Pla
   return (
     <group position={[anchorX, anchorZ, anchorY]} rotation={[0, anchorRotation, 0]}>
       {/* The part mesh extrudes along +Z; lay it flat so its face points up. */}
-      <group rotation={[-Math.PI / 2, 0, tilt * DEG_TO_RAD]}>
+      <group rotation={[-Math.PI / 2, tilt * DEG_TO_RAD, 0]}>
         <PartView part={part} baseUrl={part.baseUrl} />
       </group>
     </group>