feat(editor): live floor-stacking, unified handle system, slab-hole editing + interaction polish (#375)

- Live slab-stacking Y previews for all floor-placed kinds (item/shelf/spawn/column/stair) during placement + both move pathways, via a shared core resolver; canonical positions unchanged.
- Unified 3D handle system (one drag pipeline + one visual primitive) with forgiving invisible hit-areas on every handle, kept on EDITOR_LAYER so they don't poison the MRT scene pass.
- Hover + click-to-edit slab holes in 3D (manual hole -> hole editor; stair/elevator hole -> select owner); generic cross-arrow polygon-move grip; normalized handle interaction colors.
- NaN-safe node mutations + non-finite shadow-light bounds guard.
- Built on #373 (level-scoped alignment / registry slab tool); #373 owns X/Z alignment, this owns Y floor-stacking.

packages/nodes/src/column/definition.ts

@@ -19,6 +19,7 @@ const BRACE_HANDLE_OFFSET = 0.3
 const SPREAD_HANDLE_OFFSET = 0.22
 const ROTATE_CORNER_OFFSET = 0.32
 const ROTATE_RING_OFFSET = 0.04
+const MOVE_FRONT_OFFSET = 0.35
 const MIN_COLUMN_HEIGHT = 0.2
 const MIN_COLUMN_WIDTH = 0.1
 const MIN_COLUMN_DEPTH = 0.1
@@ -241,6 +242,29 @@ function columnRotateHandle(): HandleDescriptor<ColumnNodeType> {
   }
 }
 
+function columnMoveHandle(): HandleDescriptor<ColumnNodeType> {
+  return {
+    kind: 'translate',
+    placement: {
+      // Low to the floor at the front edge (matches the item move grip) so it
+      // reads as a floor-move grip and stays clear of the body resize / rotate
+      // handles that sit at mid-height.
+      position: (n) => {
+        const { halfZ } = columnFootprintHalf(n)
+        return [0, 0.02, halfZ + MOVE_FRONT_OFFSET]
+      },
+    },
+    apply: (_n, pos) => ({ position: [pos[0], pos[1], pos[2]] }),
+    snapExtents: (n) => {
+      const { halfX, halfZ } = columnFootprintHalf(n)
+      const dimX = Math.max(halfX * 2, MIN_COLUMN_WIDTH)
+      const dimZ = Math.max(halfZ * 2, MIN_COLUMN_DEPTH)
+      const swap = Math.abs(Math.sin(n.rotation ?? 0)) > 0.9
+      return [swap ? dimZ : dimX, swap ? dimX : dimZ]
+    },
+  }
+}
+
 function columnHandles(node: ColumnNodeType): HandleDescriptor<ColumnNodeType>[] {
   // 1. Height (universal).
   // 2. Footprint arrows depending on supportStyle + crossSection:
@@ -265,7 +289,7 @@ function columnHandles(node: ColumnNodeType): HandleDescriptor<ColumnNodeType>[]
   } else {
     handles.push(columnAxisHandle('x'), columnAxisHandle('z'))
   }
-  handles.push(columnRotateHandle())
+  handles.push(columnRotateHandle(), columnMoveHandle())
   return handles
 }
 

packages/nodes/src/column/move-tool.tsx

@@ -17,6 +17,7 @@ import {
 import {
   CursorSphere,
   DragBoundingBox,
+  getFloorStackPreviewPosition,
   markToolCancelConsumed,
   triggerSFX,
   useEditor,
@@ -74,6 +75,16 @@ function MoveColumnTool({ node }: { node: ColumnNode }) {
         ? (node.metadata as Record<string, unknown>)
         : {}
     const isNew = !!meta.isNew
+    const getVisualPosition = (
+      position: [number, number, number],
+      rotation = rotationY,
+    ): [number, number, number] =>
+      getFloorStackPreviewPosition({
+        node,
+        position,
+        rotation,
+        levelId: node.parentId ?? null,
+      })
 
     // Alignment candidates — every other alignable object's anchors, gathered
     // once (the scene graph is stable during the imperative drag).
@@ -81,19 +92,23 @@ function MoveColumnTool({ node }: { node: ColumnNode }) {
 
     const applyPreview = (position: [number, number, number]) => {
       lastPosition = position
-      setPreviewPosition(position)
+      const visualPosition = getVisualPosition(position)
+      setPreviewPosition(visualPosition)
       setPreviewRotation(rotationY)
       useLiveTransforms.getState().set(node.id, {
         position,
         rotation: rotationY,
       })
+      useScene.getState().markDirty(node.id as AnyNodeId)
       const m = sceneRegistry.nodes.get(node.id)
       if (m) {
-        m.position.set(position[0], position[1], position[2])
+        m.position.set(...visualPosition)
         m.rotation.y = rotationY
       }
     }
 
+    setPreviewPosition(getVisualPosition(node.position, node.rotation))
+
     const onGridMove = (event: GridEvent) => {
       hasMoved = true
       let x = snapToGridStep(event.localPosition[0])
@@ -145,11 +160,16 @@ function MoveColumnTool({ node }: { node: ColumnNode }) {
 
       if (nodeId && useScene.getState().nodes[nodeId]) {
         committed = true
-        useLiveTransforms.getState().clear(nodeId)
         useScene.temporal.getState().resume()
         useScene
           .getState()
           .updateNode(nodeId, { position, rotation: rotationY, ...(isNew ? { metadata: {} } : {}) })
+        useLiveTransforms.getState().clear(nodeId)
+        const m = sceneRegistry.nodes.get(nodeId)
+        if (m) {
+          m.position.set(...getVisualPosition(position, rotationY))
+          m.rotation.y = rotationY
+        }
       } else if (node.parentId) {
         const column = ColumnNodeSchema.parse({
           ...node,
@@ -174,9 +194,10 @@ function MoveColumnTool({ node }: { node: ColumnNode }) {
       useAlignmentGuides.getState().clear()
       const m = sceneRegistry.nodes.get(node.id)
       if (m) {
-        m.position.set(node.position[0], node.position[1], node.position[2])
+        m.position.set(...getVisualPosition(node.position, node.rotation))
         m.rotation.y = node.rotation
       }
+      useScene.getState().markDirty(node.id as AnyNodeId)
       useScene.temporal.getState().resume()
       markToolCancelConsumed()
       exitMoveMode()
@@ -197,9 +218,10 @@ function MoveColumnTool({ node }: { node: ColumnNode }) {
       if (!committed) {
         const m = sceneRegistry.nodes.get(node.id)
         if (m) {
-          m.position.set(node.position[0], node.position[1], node.position[2])
+          m.position.set(...getVisualPosition(node.position, node.rotation))
           m.rotation.y = node.rotation
         }
+        useScene.getState().markDirty(node.id as AnyNodeId)
         useScene.temporal.getState().resume()
       }
     }

packages/nodes/src/column/tool.tsx

@@ -13,7 +13,7 @@ import {
   useAlignmentGuides,
   useScene,
 } from '@pascal-app/core'
-import { triggerSFX, usePlacementPreview } from '@pascal-app/editor'
+import { getFloorStackPreviewPosition, triggerSFX, usePlacementPreview } from '@pascal-app/editor'
 import { useViewer } from '@pascal-app/viewer'
 import { useEffect, useMemo, useRef } from 'react'
 import type { Group } from 'three'
@@ -91,13 +91,20 @@ const ColumnTool = () => {
         useAlignmentGuides.getState().clear()
       }
 
-      cursorRef.current?.position.set(ax, event.localPosition[1], az)
+      const position: [number, number, number] = [ax, 0, az]
+      const visualPosition = getFloorStackPreviewPosition({
+        node: previewNode,
+        position,
+        rotation: previewNode.rotation,
+        levelId: activeLevelId,
+      })
+      cursorRef.current?.position.set(...visualPosition)
 
       // Publish a transient, positioned preview node for the 2D floor-plan
       // ghost (the 3D `ColumnPreview` mesh is hidden in 2D). The floor-plan
       // placement-preview layer renders this node's footprint at the snapped,
       // aligned cursor so users see the pillar before they click.
-      usePlacementPreview.getState().set({ ...previewNode, position: [ax, 0, az] })
+      usePlacementPreview.getState().set({ ...previewNode, position })
 
       const prev = previousSnapRef.current
       if (!prev || prev[0] !== ax || prev[1] !== az) {