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/core/package.json

@@ -10,6 +10,11 @@
       "types": "./dist/index.d.ts",
       "import": "./dist/index.js",
       "default": "./dist/index.js"
+    },
+    "./clone-scene-graph": {
+      "types": "./dist/utils/clone-scene-graph.d.ts",
+      "import": "./dist/utils/clone-scene-graph.js",
+      "default": "./dist/utils/clone-scene-graph.js"
     }
   },
   "files": [