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/slots.ts

@@ -1,9 +1,15 @@
 import type { SlotDeclaration } from '@pascal-app/core'
 
-export type FenceSlotId = 'surface'
+export type FenceSlotId = 'panel' | 'rail'
 
-export const FENCE_SLOT_DEFAULT = 'library:wood-finewood27'
+// Body (posts / base / infill) reads as a dark composite by default; the rail
+// cap as wood. Both are repaintable per slot.
+export const FENCE_PANEL_SLOT_DEFAULT = 'library:preset-charcoal'
+export const FENCE_RAIL_SLOT_DEFAULT = 'library:wood-finewood27'
 
 export function fenceSlots(): SlotDeclaration[] {
-  return [{ slotId: 'surface', label: 'Surface', default: FENCE_SLOT_DEFAULT }]
+  return [
+    { slotId: 'panel', label: 'Panel', default: FENCE_PANEL_SLOT_DEFAULT },
+    { slotId: 'rail', label: 'Rail', default: FENCE_RAIL_SLOT_DEFAULT },
+  ]
 }