feat: Manufacturing-grade door geometry + photorealistic materials

🏗️ Architecture (@Logic-Architect):
- Created lib/door-models.ts with exact manufacturing specs
- PROFILE_WIDTH = 40mm, PROFILE_DEPTH = 40mm (real steel tubes)
- GLASS_OFFSET = 18mm for proper centering
- Physical parts system (stiles, rails, dividers, glass)
- generateDoorAssembly() returns manufacturable parts list
- Validation for structural integrity limits

🎨 Visuals (@3D-Visual-Lead):
- Aluwdoors texture loading with vertical steel grain
- MeshStandardMaterial: roughness 0.6, metalness 0.7
- Photorealistic glass: transmission 0.98, IOR 1.5
- RoundedBox with 2mm radius for all profiles
- Suspense boundaries for progressive texture loading
- Studio environment preset + enhanced contact shadows

🔧 Technical:
- UseMemo for door assembly generation
- mmToMeters() conversion utility
- PhysicalPartComponent renderer
- Backward compatibility with glass patterns
- Fallback materials when textures fail

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

components/configurator/scene.tsx

@@ -230,17 +230,17 @@ export function Scene3D() {
       {/* Premium Studio Lighting */}
       <Lighting />
 
-      {/* City/Apartment Environment for realistic steel reflections */}
-      <Environment preset="apartment" environmentIntensity={0.6} />
+      {/* Studio Environment for photorealistic steel reflections */}
+      <Environment preset="studio" environmentIntensity={1.0} />
 
       {/* High-Resolution Contact Shadows for grounding */}
       <ContactShadows
         position={[0, 0.01, 0]}
-        opacity={0.4}
-        scale={12}
-        blur={2.5}
+        opacity={0.6}
+        scale={15}
+        blur={2}
         far={2}
-        resolution={1024}
+        resolution={2048}
       />
 
       {/* The Door - Enhanced with textures and dimensions */}