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).
Add a new characterHeightScaler runtime component and characterHeightScalerEditor for Unity to auto-detect and apply a model scale to match the GKC standard height (capture/apply/reset, foot alignment, debug UI). Update DudeAvatar materials to assign main textures, clear legacy shader keywords and enable XR motion vectors. Modify launchObject material to use transparent surface settings, correct render queue/blend/ZWrite and disabled shadow/depth passes for proper particle rendering. Update ParticlesLight prefab to include UniversalAdditionalLightData and URP-related light fields (cookie size, shadow & rendering layers, etc.). Add new Flaco alien folder with prefabs/meshes and new house materials; remove some legacy alien FBX files. Also include Scene and ProjectSettings updates to accommodate the changes.
Add a new House asset (Assets/Game/House/CasaExample.fbx) with corresponding meta and folder metadata. Adjust World Canvas material (removed _SPECULAR_COLOR, disabled SHADOWCASTER pass, enabled XR motion vectors flag) and update Save Camera RenderTexture serialized settings. Update SampleScene LFS entry and bump Unity package versions in Packages/manifest.json (several dependency version updates). Also update ProjectSettings (project asset/hash and ProjectVersion to 6000.3.8f1).
