Phase 5 Stage D ceiling: port placement + move + boundary/hole editors

Replicates the slab Stage D recipe for ceiling: four affordances
routed through the registry — def.tool for the placement flow,
def.affordanceTools for boundary edit / hole edit / whole-ceiling move.

Ceiling-specific bits preserved:
- Placement tool keeps the dual-cursor + vertical TSL-gradient
  connector + ground-shadow lines (1:1 with legacy).
- Move tool wrapper renders the translucent preview fill + outline
  overlay so the user sees the destination before clicking.

ToolManager mount sites for CeilingBoundaryEditor / CeilingHoleEditor
now route through `getRegistryAffordanceTool` with legacy fallback.

Per-kind progress: ceiling A ✅ B (n/a, def.renderer escape hatch
preserved) C ✅ D ✅; E + F pending.

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

packages/nodes/src/ceiling/boundary-editor.tsx

@@ -0,0 +1,47 @@
+'use client'
+
+import { type CeilingNode, resolveLevelId, useScene } from '@pascal-app/core'
+import { PolygonEditor } from '@pascal-app/editor'
+import { useViewer } from '@pascal-app/viewer'
+import { useCallback } from 'react'
+
+/**
+ * Phase 5 Stage D — ceiling boundary editor (registry-driven).
+ *
+ * Thin wrapper around the shared `<PolygonEditor>` (same shape as
+ * slab's boundary-editor). Activates when a ceiling is selected in
+ * structure/select mode and no hole edit is in progress.
+ */
+export const CeilingBoundaryEditor: React.FC<{ ceilingId: CeilingNode['id'] }> = ({
+  ceilingId,
+}) => {
+  const ceilingNode = useScene((s) => s.nodes[ceilingId])
+  const updateNode = useScene((s) => s.updateNode)
+  const setSelection = useViewer((s) => s.setSelection)
+
+  const ceiling = ceilingNode?.type === 'ceiling' ? (ceilingNode as CeilingNode) : null
+
+  const handlePolygonChange = useCallback(
+    (newPolygon: Array<[number, number]>) => {
+      updateNode(ceilingId, { polygon: newPolygon })
+      setSelection({ selectedIds: [ceilingId] })
+    },
+    [ceilingId, updateNode, setSelection],
+  )
+
+  if (!ceiling?.polygon || ceiling.polygon.length < 3) return null
+
+  return (
+    <PolygonEditor
+      allowEdgeMove
+      color="#d4d4d4"
+      levelId={resolveLevelId(ceiling, useScene.getState().nodes)}
+      minVertices={3}
+      onPolygonChange={handlePolygonChange}
+      polygon={ceiling.polygon}
+      surfaceHeight={ceiling.height ?? 2.5}
+    />
+  )
+}
+
+export default CeilingBoundaryEditor