feat(editor): route door/window facing triangle through the unified overlay

Door and window are placed via preset and moved with a bespoke wall-bound
`move-tool` (affordanceTools.move), not the draw tool — so the previous inline
triangle never showed for the paths actually used. Migrate both:

- move-tool (move + preset, the community path): publish the on-wall ghost pose
  to `useFacingPose` in the same building-local frame the ghost renders in,
  dropped to the floor under the wall (the ghost Y is the opening centre); clear
  on every off-wall / hide / reveal / unmount path
- draw tool (standalone from-scratch path): publish the on-host pose, clear on
  fallback/hide; frame depth read via a ref to keep the setup effect deps clean

Removes the now-dead `FacingIndicator` public export (the editor-side overlay is
its only consumer, via relative import). The unified overlay now covers every
placement/move path: items, column/shelf, stair, and door/window.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

packages/editor/src/index.tsx

@@ -88,7 +88,6 @@ export {
 } from './components/tools/item/use-placement-coordinator'
 export { CursorSphere } from './components/tools/shared/cursor-sphere'
 export { DragBoundingBox } from './components/tools/shared/drag-bounding-box'
-export { FacingIndicator } from './components/tools/shared/facing-indicator'
 export { getFloorStackPreviewPosition } from './components/tools/shared/floor-stack-preview'
 export { useFreshPlacementVisibility } from './components/tools/shared/fresh-placement-visibility'
 // Phase 5 Stage D — PolygonEditor for slab/ceiling boundary + hole editors.