feat(paint-slots): round-2 feedback — fence 2 slots + UVs, roof defaults, stair body

- fence: split into two paint slots — panel (posts/base/infill, default charcoal)
  and rail (cap, default wood-finewood27) — as separate meshes with userData.slotId.
  Fix applyFenceUVs to continuous world-space 1 UV unit = 1 m (drop the per-part
  min origin that broke tiling across parts). New generateFenceSlotGeometries.
- roof: real catalog defaults for the segment surfaces via getRoofMaterialArray
  (the actual default path): wall/trim concrete-plate (matches walls), deck +
  soffit soft-white, shingle terracotta; textures-off role escape hatch kept.
  Align nodes getRoofMaterials no-parent fallback to match.
- stair: body slot default -> preset-lightgrey.
- (biome formatting normalization of the round-1 merged renderer files rides along.)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/nodes/src/fence/paint.ts

@@ -1,8 +1,13 @@
-import type { AnyNode, FenceNode } from '@pascal-app/core'
+import type { AnyNode, FenceNode, PaintResolveArgs } from '@pascal-app/core'
 import { createSlotPaintCapability, previewGeometrySlot } from '../shared/slot-paint'
 
+function resolveFenceRole(args: PaintResolveArgs): string | null {
+  const slotId = (args.hitObject?.userData as { slotId?: unknown } | undefined)?.slotId
+  return slotId === 'panel' || slotId === 'rail' ? slotId : null
+}
+
 export const fencePaint = createSlotPaintCapability({
-  resolveRole: () => 'surface',
+  resolveRole: resolveFenceRole,
   applyPreview: previewGeometrySlot,
   legacyEffective: (node: AnyNode) => {
     const fence = node as FenceNode