Proves the unified (nodeId, slotId) slot contract on a procedural generator,
beyond items and walls. A shelf now exposes three paintable slots — shelves /
frame / back — painted through the same PaintCapability dispatch and the same
node.slots: Record<slotId, MaterialRef> shape items use.
Foundation (shared, reusable by future procedural kinds):
- core: SlotDeclaration type + capabilities.slots(node) registry declaration;
GeometryContext gains `materials` so a pure builder can resolve scene:<id>
slot refs without importing useScene.
- viewer GeometrySystem: threads the scene material library into every builder
ctx, and re-dirties (bypassing the geometryKey skip) any geometry node that
references a scene material when that material changes — so editing a custom
colour propagates to every shelf using it, matching items.
Shelf:
- schema: slots: Record<string, MaterialRef> (mirrors ItemNode).
- geometry: per-slot material resolution (slot override -> legacy whole-shelf
-> declared default colour); every mesh stamped with userData.slotId;
DEFAULT_SHELF_MATERIAL retired (declared default gives identical off-white).
- paint.ts: PaintCapability (resolveRole from userData.slotId, scene-material
commit for one-off colours, preview restricted to __fromGeometry meshes so
hosted items aren't ghosted, getEffectiveMaterial incl. legacy fallback).
- definition: paint + slots capabilities; slots folded into geometryKey.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
