feat: refine nightdrive world and authored car

Integrate the Blender grand tourer with a cohesive shader-driven road, terrain, atmosphere, lighting, and post-processing pass. Refine responsive drive dynamics and sign lifecycle behavior, and add durable visual, accessibility, and performance verification evidence.

assets/blender/nightdrive-grand-tourer.asset.json

@@ -0,0 +1,19 @@
+{
+  "name": "Nightdrive Grand Tourer",
+  "source": "Original Blender model created for this portfolio",
+  "license": "Original work",
+  "thirdPartyAssets": [],
+  "externalProviders": [],
+  "polyHavenAssets": [],
+  "sourceFile": "nightdrive-grand-tourer.blend",
+  "exportFile": "../../src/assets/nightdrive-grand-tourer.glb",
+  "exportProfile": {
+    "format": "GLB",
+    "meshObjects": 8,
+    "triangles": 11560,
+    "materials": 8,
+    "textures": 0,
+    "animations": 0,
+    "bytes": 410408
+  }
+}