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 Pause Menu UI (UXML, USS, TSS, asset/meta) and related UI folder metadata. Add new terrain assets and TerrainData files, plus lighting settings for the 2.5d demo scene. Import a new character model (X Bot.fbx) with its importer meta and new characters folder. Update SampleScene and LFS pointers, and refresh render pipeline settings (Mobile RP & URP global settings) and project/package settings. Tweak multiple material files: align _Color with BaseColor, add SHADOWCASTER to disabled shader passes for Ellen materials, and assign a missing main texture for Vincent_Hero_High_diffuse.
