sync: comprehensive monorepo → editor parity (2D/3D decoupling, UX polish, crash fixes)

Squash merge of 3 commits:
1. useLiveTransforms store for 2D/3D decoupling + floorplan overhaul + Sentry crash fixes
2. Comprehensive 59-file sync bringing editor to full monorepo parity (selection highlights, delete tool, furnish/zone modes, keyboard shortcuts, all panels)
3. Missing files fix (materials.ts, merged-outline-node.ts, type fix)

75 files changed, ~6K additions.

packages/viewer/src/components/viewer/index.tsx

@@ -1,9 +1,5 @@
 'use client'
 
-// Must run before @react-three/fiber's Canvas instantiates new THREE.Clock().
-// See lib/suppress-three-clock-warning.ts for rationale and removal condition.
-import '../../lib/suppress-three-clock-warning'
-
 import {
   CeilingSystem,
   DoorSystem,
@@ -19,7 +15,6 @@ import { Canvas, extend, type ThreeToJSXElements, useFrame, useThree } from '@re
 import { useEffect, useMemo, useRef } from 'react'
 import * as THREE from 'three/webgpu'
 import useViewer from '../../store/use-viewer'
-import { ExportSystem } from '../../systems/export/export-system'
 import { GuideSystem } from '../../systems/guide/guide-system'
 import { ItemLightSystem } from '../../systems/item-light/item-light-system'
 import { LevelSystem } from '../../systems/level/level-system'
@@ -151,7 +146,6 @@ const Viewer: React.FC<ViewerProps> = ({
       <WallSystem />
       <WindowSystem />
       <ZoneSystem />
-      <ExportSystem />
       <PostProcessing />
       {/* <DebugRenderer /> */}
       <GPUDeviceWatcher />