Phase 5 Stage E: full kind migration into packages/nodes

Wholesale move of every remaining kind into its own subdirectory under
`packages/nodes/src/`, finishing the registry-driven migration. Each
kind now ships its definition, schema (re-exported from core), and any
of `geometry` / `renderer` / `system` / `floorplan` / `tool` /
`move-tool` / `panel` / `floorplan-move` / `floorplan-affordances` /
`parametrics` / `preview` it needs — no per-kind code remains under
`packages/editor/src/components/tools/` or
`packages/viewer/src/components/renderers/`.

Deleted (replaced by registry-driven equivalents):
- `tools/{ceiling,column,door,fence,item,slab,spawn,wall,window}/...`
  (boundary editors, hole editors, placement tools, move tools,
  endpoint movers, curve tools, helpers, math libs)
- `ui/helpers/{ceiling,slab,wall}-helper.tsx`
- `ui/panels/{column,door,elevator,item,roof,roof-segment,spawn,
  stair,stair-segment,wall,window}-panel.tsx`
- `viewer/src/components/renderers/{building,ceiling,column,door,
  elevator,fence,guide,item,level,roof,roof-segment,scan,site,slab,
  spawn,stair,stair-segment,wall,window,zone}-renderer.tsx`
- `viewer/src/components/viewer/legacy-system.tsx`

Added under `packages/nodes/src/`:
- `building/`, `column/`, `elevator/`, `guide/`, `level/`, `roof/`,
  `roof-segment/`, `scan/`, `shared/`, `site/`, `stair/`,
  `stair-segment/` packages with definition + schema + renderer / system
  / floorplan / panel as appropriate.
- New `floorplan-move.ts` for every kind that supports 2D moves
  (ceiling, door, item, shelf, slab, window) — single registry-driven
  dispatch path via `def.floorplanMoveTarget`.
- New `floorplan-affordances.ts` for kinds with polygon / endpoint
  drags (ceiling, fence, slab, wall) — using the shared
  `polygon-vertex-affordance` factories.
- New per-kind `panel.tsx` for kinds with custom inspector content
  (door, item, shelf, spawn, wall, window).
- New per-kind `tool.tsx` for placement (door, item, shelf, window).
- New per-kind `move-tool.tsx` for kinds with custom 3D move flows
  (door, item, slab, window).

Coordinator + manager updates in `packages/editor/`:
- `tool-manager.tsx` resolves tools from the registry only — no
  hardcoded type→component map.
- `panel-manager.tsx` resolves inspector panels the same way.
- `placement-{coordinator,strategies,types}.ts` extended with
  shelf-surface placement.
- `selection-manager.tsx` adds the registry-selectable fallback.
- `floorplan-panel.tsx`, `floorplan-background-placement.ts`,
  `floorplan-render-context.tsx` updated for the registry layer's new
  contract (props, affordance dispatch, render context).

Viewer updates:
- `viewer/index.tsx` drops legacy renderer mounts.
- `node-renderer.tsx` resolves by registry only.
- `scene-bvh.tsx`, `use-node-events.ts`, `level-system.tsx`,
  `wall-cutout.tsx`, `zone-system.tsx`, `materials.ts` adjusted for
  the registry-only world.

Sidebar tree nodes for ceiling / fence / slab / shelf / tree-node
updated to read from the registered nodes instead of the deleted
legacy renderer trees.

Wiki: new `plugin-authoring.md` page, README index updated.

Tests in `packages/nodes/src/index.test.ts` validate every registered
kind has the required shape.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

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

@@ -0,0 +1,119 @@
+'use client'
+
+import {
+  type AnyNodeId,
+  type ColumnNode,
+  ColumnNode as ColumnNodeSchema,
+  emitter,
+  type GridEvent,
+  sceneRegistry,
+  useLiveTransforms,
+  useScene,
+} from '@pascal-app/core'
+import { CursorSphere, markToolCancelConsumed, triggerSFX, useEditor } from '@pascal-app/editor'
+import { useCallback, useEffect, useState } from 'react'
+
+/**
+ * Phase 5 Stage D — column's registry-driven 3D move affordance.
+ *
+ * Replaces the legacy `MoveColumnTool` in `editor/src/components/tools/
+ * column/move-column-tool.tsx`. Behaviour is identical: grid:move
+ * snaps the cursor to a 0.5m grid and previews the column at that
+ * position via `useLiveTransforms` + a direct `sceneRegistry.nodes.get
+ * (id).position.set(...)` (the live-drag exception documented in
+ * `wiki/architecture/tools.md`); grid:click commits via `useScene.
+ * updateNode`. Cancel restores the pre-drag position.
+ *
+ * Wired via `def.affordanceTools.move`. The editor's `MoveTool`
+ * dispatcher's `getRegistryAffordanceTool('column', 'move')` lookup
+ * picks this up before its legacy chain reaches `<MoveColumnTool>`.
+ */
+const roundToHalf = (value: number) => Math.round(value * 2) / 2
+
+function MoveColumnTool({ node }: { node: ColumnNode }) {
+  const [previewPosition, setPreviewPosition] = useState<[number, number, number]>(node.position)
+
+  const exitMoveMode = useCallback(() => {
+    useEditor.getState().setMovingNode(null)
+  }, [])
+
+  useEffect(() => {
+    useScene.temporal.getState().pause()
+    let committed = false
+
+    const applyPreview = (position: [number, number, number]) => {
+      setPreviewPosition(position)
+      useLiveTransforms.getState().set(node.id, {
+        position,
+        rotation: node.rotation,
+      })
+      sceneRegistry.nodes.get(node.id)?.position.set(position[0], position[1], position[2])
+    }
+
+    const onGridMove = (event: GridEvent) => {
+      applyPreview([roundToHalf(event.localPosition[0]), 0, roundToHalf(event.localPosition[2])])
+    }
+
+    const onGridClick = (event: GridEvent) => {
+      const position: [number, number, number] = [
+        roundToHalf(event.localPosition[0]),
+        0,
+        roundToHalf(event.localPosition[2]),
+      ]
+      const nodeId = (node as { id?: ColumnNode['id'] }).id
+
+      if (nodeId && useScene.getState().nodes[nodeId]) {
+        committed = true
+        useLiveTransforms.getState().clear(nodeId)
+        useScene.temporal.getState().resume()
+        useScene.getState().updateNode(nodeId, { position })
+      } else if (node.parentId) {
+        const column = ColumnNodeSchema.parse({
+          ...node,
+          id: undefined,
+          metadata: {},
+          position,
+        })
+        committed = true
+        useScene.temporal.getState().resume()
+        useScene.getState().createNode(column, node.parentId as AnyNodeId)
+      }
+
+      useLiveTransforms.getState().clear(node.id)
+      triggerSFX('sfx:item-place')
+      exitMoveMode()
+      event.nativeEvent?.stopPropagation?.()
+    }
+
+    const onCancel = () => {
+      useLiveTransforms.getState().clear(node.id)
+      sceneRegistry.nodes
+        .get(node.id)
+        ?.position.set(node.position[0], node.position[1], node.position[2])
+      useScene.temporal.getState().resume()
+      markToolCancelConsumed()
+      exitMoveMode()
+    }
+
+    emitter.on('grid:move', onGridMove)
+    emitter.on('grid:click', onGridClick)
+    emitter.on('tool:cancel', onCancel)
+
+    return () => {
+      emitter.off('grid:move', onGridMove)
+      emitter.off('grid:click', onGridClick)
+      emitter.off('tool:cancel', onCancel)
+      useLiveTransforms.getState().clear(node.id)
+      if (!committed) {
+        sceneRegistry.nodes
+          .get(node.id)
+          ?.position.set(node.position[0], node.position[1], node.position[2])
+        useScene.temporal.getState().resume()
+      }
+    }
+  }, [exitMoveMode, node])
+
+  return <CursorSphere color="#a78bfa" height={node.height} position={previewPosition} />
+}
+
+export default MoveColumnTool