sync: update core and viewer from monorepo (#143)

Major changes:
- Roof system rewrite with roof-segment support
- Scene store refactor
- Spatial grid improvements
- Item light system
- Post-processing and selection manager updates
- Perf monitor component

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/viewer/src/store/use-viewer.ts

@@ -61,6 +61,9 @@ type ViewerState = {
   exportScene: (() => Promise<void>) | null
   setExportScene: (fn: (() => Promise<void>) | null) => void
 
+  debugColors: boolean
+  setDebugColors: (enabled: boolean) => void
+
   cameraDragging: boolean
   setCameraDragging: (dragging: boolean) => void
 }
@@ -173,6 +176,9 @@ const useViewer = create<ViewerState>()(
       exportScene: null,
       setExportScene: (fn) => set({ exportScene: fn }),
 
+      debugColors: false,
+      setDebugColors: (enabled) => set({ debugColors: enabled }),
+
       cameraDragging: false,
       setCameraDragging: (dragging) => set({ cameraDragging: dragging }),
     }),