fix: bump @github/copilot to 1.0.15-1, remove spurious root package-lock

Author: SteveSandersonMS

nodejs/package-lock.json

@@ -56,7 +56,7 @@
   "author": "GitHub",
   "license": "MIT",
   "dependencies": {
-    "@github/copilot": "^1.0.14-0",
+    "@github/copilot": "^1.0.15-1",
     "vscode-jsonrpc": "^8.2.1",
     "zod": "^4.3.6"
   },