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>

packages/nodes/src/window/definition.ts

@@ -2,9 +2,12 @@ import type {
   AnyNodeId,
   HandleDescriptor,
   NodeDefinition,
+  RoofSegmentNode,
   WallNode,
   WindowNode as WindowNodeType,
 } from '@pascal-app/core'
+import { readRoofFaceHeightMax, readRoofFaceWidthMax } from '../shared/roof-opening-host'
+import { buildRoofWallOpeningCut } from '../shared/roof-wall-opening-cut'
 import { buildWindowFloorplan } from './floorplan'
 import { windowWidthAffordance } from './floorplan-affordances'
 import { windowFloorplanMoveTarget } from './floorplan-move'
@@ -36,7 +39,13 @@ function windowWidthHandle(side: 'left' | 'right'): HandleDescriptor<WindowNodeT
     axis: 'x',
     anchor: side === 'right' ? 'min' : 'max',
     min: MIN_WINDOW_WIDTH,
-    max: (n, scene) => readWallLength(n, scene),
+    max: (n, scene) => {
+      // Roof-hosted windows clamp against the face profile (the
+      // wall-based limits read Infinity when wallId is unset).
+      const roofMax = readRoofFaceWidthMax(n, scene, sign)
+      if (roofMax !== null) return Math.max(MIN_WINDOW_WIDTH, roofMax)
+      return readWallLength(n, scene)
+    },
     currentValue: (n) => n.width,
     apply: (initial, newWidth) => {
       const rotY = initial.rotation[1]
@@ -73,6 +82,8 @@ function windowHeightHandle(edge: 'top' | 'bottom'): HandleDescriptor<WindowNode
     anchor: edge === 'top' ? 'min' : 'max',
     min: MIN_WINDOW_HEIGHT,
     max: (n, scene) => {
+      const roofMax = readRoofFaceHeightMax(n, scene, sign)
+      if (roofMax !== null) return Math.max(MIN_WINDOW_HEIGHT, roofMax)
       // Maximum: distance from the anchored edge to the wall's allowed Y
       // bounds. Top arrow caps at wall.height - bottom; bottom arrow caps
       // at top (positive Y room above the floor).
@@ -139,9 +150,18 @@ export const windowDefinition: NodeDefinition<typeof WindowNode> = {
     duplicable: true,
     deletable: true,
     wallOpeningPlacement: true,
-    // `wallId` is re-derived from the wall under the cursor at preset
-    // placement time — see the door capability for the same pattern.
-    hostRefFields: ['wallId'],
+    // Windows also host on roof-segment wall faces (base walls under the
+    // roof, gable ends) — same wiring as door; see the door capability
+    // for why `cascadesViaHostSegment` is required.
+    roofAccessory: {
+      buildCut: (node, hostSegment) =>
+        buildRoofWallOpeningCut(node as WindowNodeType, hostSegment as RoofSegmentNode),
+      cutScope: 'wall',
+      cascadesViaHostSegment: true,
+    },
+    // `wallId` / `roofSegmentId` are re-derived from the surface under
+    // the cursor at preset placement time — see door for the pattern.
+    hostRefFields: ['wallId', 'roofSegmentId'],
   },
 
   parametrics: windowParametrics,