Migrate to full 3D visualizer with React Three Fiber

Complete architectural overhaul from CSS to WebGL 3D rendering:

**Dependencies Added:**
- three, @types/three
- @react-three/fiber (R3F)
- @react-three/drei (helpers)

**New Components:**

1. components/configurator/scene.tsx
   - Canvas with shadows and tone mapping
   - PerspectiveCamera with OrbitControls
   - Lighting: Ambient + Directional + Spot + Environment
   - 3D Room: Floor (wood texture) + Walls with doorway opening
   - Limited camera rotation (minPolarAngle/maxPolarAngle)

2. components/configurator/door-3d.tsx
   - Door constructed from 3D mesh primitives (BoxGeometry)
   - Frame: Metal material (metalness 0.7, roughness 0.3)
   - Glass: PhysicalMaterial with transmission for realistic glass
   - Dynamic grid dividers based on gridType
   - Handles: 3D U-greep (vertical bar) or Klink (horizontal + sphere)
   - All meshes cast shadows

3. components/configurator/door-visualizer.tsx
   - Integrated Scene3D with Suspense
   - Loading fallback with spinner
   - Control hints for user interaction
   - Badge changed to "3D Voorbeeld"

**Features:**
- True depth and perspective
- Realistic shadows on floor and walls
- Reflective glass material
- Interactive camera (drag to rotate, scroll to zoom)
- Door appears IN the doorway, not floating
- Apartment environment preset for reflections
- Real-time updates from Zustand store

**Result:** Photorealistic 3D room with proper lighting, shadows, and materials

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

package.json

@@ -10,6 +10,9 @@
   },
   "dependencies": {
     "@hookform/resolvers": "^5.2.2",
+    "@react-three/drei": "^10.7.7",
+    "@react-three/fiber": "^9.5.0",
+    "@types/three": "^0.182.0",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
     "lucide-react": "^0.563.0",
@@ -19,6 +22,7 @@
     "react-dom": "19.2.3",
     "react-hook-form": "^7.71.1",
     "tailwind-merge": "^3.4.0",
+    "three": "^0.182.0",
     "zod": "^4.3.6",
     "zustand": "^5.0.11"
   },