refactor: release-review cleanup for roof wall openings

Dual review pass (Claude multi-angle + Codex release-quality). One
correctness fix and the agreed do-now cleanups:

- fix: clone-scene-graph remaps roofSegmentId like wallId in both
  clone paths — duplicated scenes/levels kept pointing roof-hosted
  children at the original segments.
- extract the settled, stateless roof target/cursor math shared by the
  four door/window tools into shared/roof-wall-opening-placement.ts
  (resolveRoofWallOpeningTarget + getRoofWallOpeningCursorPose +
  worldToSelectedBuildingLocal); tools keep the stateful lifecycle
  (drafts, undo/temporal, commit field lists). −199 net lines.
- rename host-generic state: currentWallId→currentHostId,
  markWallDirty→markHostDirty (they hold segment ids too); capability
  cascadesViaHostSegment→dirtyHandledByOwnSystem (behavior-facing,
  before the public API hardens).
- drop getRoofAccessoryKinds from core's public API — its only caller
  was the standalone Build tab, which now enumerates the registry
  inline with its app-specific filter.
- window move-tool uses the shared stripPlacementMetadataFlags; stale
  "segment-local" comment fixed.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

packages/core/src/utils/clone-scene-graph.ts

@@ -76,6 +76,13 @@ export function cloneSceneGraph(sceneGraph: SceneGraph): SceneGraph {
         | undefined
     }
 
+    // Remap roofSegmentId (doors/windows/items hosted on roof wall faces)
+    if ('roofSegmentId' in clonedNode && typeof clonedNode.roofSegmentId === 'string') {
+      ;(clonedNode as Record<string, unknown>).roofSegmentId = idMap.get(
+        clonedNode.roofSegmentId,
+      ) as string | undefined
+    }
+
     clonedNodes[newId] = clonedNode
   }
 
@@ -220,6 +227,12 @@ export function cloneLevelSubtree(
       ;(cloned as Record<string, unknown>).wallId = idMap.get(cloned.wallId) ?? cloned.wallId
     }
 
+    // Remap roofSegmentId (doors/windows/items hosted on roof wall faces)
+    if ('roofSegmentId' in cloned && typeof cloned.roofSegmentId === 'string') {
+      ;(cloned as Record<string, unknown>).roofSegmentId =
+        idMap.get(cloned.roofSegmentId) ?? cloned.roofSegmentId
+    }
+
     clonedNodes.push(cloned)
   }