Use clean ToyCar model and lane-offset cruise route

assets/vehicles/README.md

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+# Vehicle Assets
+
+## ToyCar.glb
+
+- Source: Khronos glTF Sample Assets, `Toy Car`
+- URL: https://github.com/KhronosGroup/glTF-Sample-Assets/tree/main/Models/ToyCar
+- License summary from Khronos model list: CC0 1.0 Universal
+- Credit: © 2017, Analytical Graphics, Inc.
+
+Used only by the experimental Cesium vehicle cruise preview.