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/Scenes/MainMenu.unity

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:33b322a5c7e9edc0fc5511ae8b7410ec6f011933c93ee2bd9a58b4097ecfb8fc
+size 13438

Assets/Scenes/MainMenu.unity.meta

@@ -0,0 +1,7 @@
+fileFormatVersion: 2
+guid: a9a2cf255bad9d7418d390f3ea30056f
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/Scenes/SampleScene.unity

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:56edc327c29adb9fcabf9e18af76d07a5415b61fdb5b8b06e82bf90208ec911a
-size 28240480
+oid sha256:7e0b1e126c1e421607130c53f1628b000363b21d2ac17d2cc8edda1bde19303c
+size 115045830