Initial commit: Unity Needle AR Menu project with MenuScene and SampleScene web apps

Add root .gitignore for Unity Library/Temp/Logs, IDE folders, and node_modules.
Include Assets, Needle TypeScript (MenuController, asset picker, WebXR), and project configuration.

Made-with: Cursor

ProjectSettings/XRSettings.asset

@@ -0,0 +1,10 @@
+{
+    "m_SettingKeys": [
+        "VR Device Disabled",
+        "VR Device User Alert"
+    ],
+    "m_SettingValues": [
+        "False",
+        "False"
+    ]
+}