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/nodes/src/door/definition.ts

@@ -160,14 +160,14 @@ export const doorDefinition: NodeDefinition<typeof DoorNode> = {
     wallOpeningPlacement: true,
     // Doors also host on roof-segment wall faces (base walls under the
     // roof, gable ends). `buildCut` punches the opening into the
-    // segment's wall brush; `cascadesViaHostSegment` keeps the roof-merge
+    // segment's wall brush; `dirtyHandledByOwnSystem` keeps the roof-merge
     // loop from consuming door dirty marks (DoorSystem owns them and
     // already cascades to the host via parentId).
     roofAccessory: {
       buildCut: (node, hostSegment) =>
         buildRoofWallOpeningCut(node as DoorNodeType, hostSegment as RoofSegmentNode),
       cutScope: 'wall',
-      cascadesViaHostSegment: true,
+      dirtyHandledByOwnSystem: true,
     },
     // `wallId` / `roofSegmentId` tie the door to its host and are
     // re-derived from the surface under the cursor when a preset is