feat: doors and windows on roof-segment wall faces

Openings now host on the walls a roof segment generates — the base
walls under the roof and the coplanar gable/shed/gambrel end faces, so
a window can sit in a gable pediment.

- core: roof-segment-walls.ts models the four vertical faces as 2D
  frames (u along face, v height) with convex profile polygons that
  mirror the wall volume getRoofSegmentBrushes builds; rect-in-profile
  clamping and anchored resize limits via half-plane algebra.
- schemas: optional roofSegmentId on door/window; position is the
  segment-local wall mid-plane center, rotation[1] the face yaw.
- cut: reuses capabilities.roofAccessory.buildCut; new cutScope: 'wall'
  subtracts from the wall brush only. cascadesViaHostSegment keeps the
  roof-merge loop from consuming door/window dirty marks (their own
  systems cascade via parentId).
- tools: roof:* handlers in door/window tool + move-tool (the Build-tab
  preset path), with roofSegmentId cleared/restored across every
  roof<->wall re-anchor and revert; shared hit resolver normalizes
  normals through world space (merged mesh vs painted segment frames).
- fix: RoofSystem no longer rebuilds per-segment CSG in accessory-reveal
  mode — the uncut rebuild used to draw over the merged shell's fresh
  opening until deselect.
- fix: the walkthrough collider world now prunes by renderer-effective
  visibility; stale uncut segment CSG inside the hidden segments-wrapper
  blocked the player at openings the merged shell had cut through.

Known gap: painted segments render per-segment CSG without accessory
cuts (pre-existing, also affects skylight/dormer). Twice Codex-reviewed;
details in private-editor plans/editor-roof-wall-openings.md.

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

apps/editor/components/build-tab.tsx

@@ -118,14 +118,19 @@ export function BuildTab() {
   // app bootstrap, so enumerating earlier would race it and see no kinds.
   const roofFeatures = useMemo<RoofFeature[]>(
     () =>
-      getRoofAccessoryKinds().map((kind) => {
-        const icon = nodeRegistry.get(kind)?.presentation?.icon
-        return {
-          kind,
-          label: nodeRegistry.get(kind)?.presentation?.label ?? kind,
-          iconSrc: icon?.kind === 'url' ? icon.src : ROOF_FEATURE_FALLBACK_ICON,
-        }
-      }),
+      getRoofAccessoryKinds()
+        // Door / window declare `roofAccessory` for the wall-face cut but
+        // already have their own Build tiles — listing them here too
+        // would duplicate the entry under Roof → Features.
+        .filter((kind) => !nodeRegistry.get(kind)?.capabilities?.wallOpeningPlacement)
+        .map((kind) => {
+          const icon = nodeRegistry.get(kind)?.presentation?.icon
+          return {
+            kind,
+            label: nodeRegistry.get(kind)?.presentation?.label ?? kind,
+            iconSrc: icon?.kind === 'url' ? icon.src : ROOF_FEATURE_FALLBACK_ICON,
+          }
+        }),
     [],
   )