Update onCreateCommand to set npm registry and install Copilot

Author: hubwriter

.devcontainer/devcontainer.json

@@ -59,7 +59,12 @@
   },
 
   // Lifecycle commands
-  "onCreateCommand": "npm ci",
+  "onCreateCommand": [
+    "npm set \"//npm.pkg.github.com/:_authToken=$GITHUB_TOKEN\"",
+    "npm set \"@github:registry=https://npm.pkg.github.com/\"",
+    "npm install -g @github/copilot",
+    "npm ci"
+  ],
   "postStartCommand": "nohup bash -c 'npm start &'",
   // Set the port to be public
   "postAttachCommand": "gh cs ports visibility 4000:public -c \"$CODESPACE_NAME\"",