Add Main Menu UI, alien models & editor configs

Add VS Code workspace/launch/settings for Unity development and a new MainMenu scene/UI (uxml, uss, tss) with MainMenuController and related assets. Import two alien character FBX models (with generated .meta settings) and add folder metadata. Update Git LFS pointers for a Game Kit scene and add modifications to Game Kit Controller assets (World Canvas material and Save Camera render texture) and ProjectSettings/QualitySettings. These changes bring initial UI/menu assets and character models into the project and add editor tooling/config for easier development.

Assets/Game Kit Controller/Shaders/World Canvas.mat

@@ -26,6 +26,7 @@ Material:
   m_ModifiedSerializedProperties: 0
   m_ValidKeywords:
   - _ALPHAPREMULTIPLY_ON
+  - _SPECULAR_COLOR
   - _SURFACE_TYPE_TRANSPARENT
   m_InvalidKeywords: []
   m_LightmapFlags: 4
@@ -37,7 +38,6 @@ Material:
   disabledShaderPasses:
   - MOTIONVECTORS
   - DepthOnly
-  - SHADOWCASTER
   m_LockedProperties: 
   m_SavedProperties:
     serializedVersion: 3
@@ -158,7 +158,6 @@ Material:
     - _Surface: 1
     - _UVSec: 0
     - _UseUIAlphaClip: 0
-    - _XRMotionVectorsPass: 1
     - _ZWrite: 0
     m_Colors:
     - _BaseColor: {r: 1, g: 1, b: 1, a: 1}

Assets/Game Kit Controller/Textures/Render Texture/Save Camera.renderTexture

@@ -3,29 +3,20 @@
 --- !u!84 &8400000
 RenderTexture:
   m_ObjectHideFlags: 0
-  m_CorrespondingSourceObject: {fileID: 0}
-  m_PrefabInstance: {fileID: 0}
-  m_PrefabAsset: {fileID: 0}
+  m_PrefabParentObject: {fileID: 0}
+  m_PrefabInternal: {fileID: 0}
   m_Name: Save Camera
   m_ImageContentsHash:
     serializedVersion: 2
     Hash: 00000000000000000000000000000000
-  m_IsAlphaChannelOptional: 0
-  serializedVersion: 6
   m_Width: 256
   m_Height: 256
   m_AntiAliasing: 1
-  m_MipCount: -1
-  m_DepthStencilFormat: 92
-  m_ColorFormat: 8
+  m_DepthFormat: 2
+  m_ColorFormat: 0
   m_MipMap: 0
   m_GenerateMips: 1
   m_SRGB: 0
-  m_UseDynamicScale: 0
-  m_UseDynamicScaleExplicit: 0
-  m_BindMS: 0
-  m_EnableCompatibleFormat: 1
-  m_EnableRandomWrite: 0
   m_TextureSettings:
     serializedVersion: 2
     m_FilterMode: 1
@@ -36,4 +27,3 @@ RenderTexture:
     m_WrapW: 1
   m_Dimension: 2
   m_VolumeDepth: 1
-  m_ShadowSamplingMode: 2