Bulk delete of Game Kit Controller content: removes many demo models, animations, textures, materials, prefabs, particle/terrain assets and a large set of inventory capture images. This is a cleanup to remove third-party/demo art and large binary assets from the repository (no code changes).
Bulk-updates Mixamo material assets under Assets/Mixamo Animations to the Universal Render Pipeline material layout (serializedVersion -> 8). Shader references were replaced with the URP shader GUID, an AssetVersion MonoBehaviour block was added, and many new material properties were added/normalized (BaseMap/_BaseColor/_SpecColor, SpecGlossMap, unity_Lightmaps/unity_ShadowMasks, various floats/ints like _Smoothness/_Cull/_Surface/_WorkflowMode, disabled MOTIONVECTORS pass, etc.). ProjectSettings.asset was also modified (likely to reflect the pipeline update). These changes align materials with URP serialization and rendering expectations.
