The opengenui route used the nonexistent model id "openai/gpt-5.2", causing
every chat turn to error. Switch to "openai/gpt-4o", the verified-real id used
by the sibling showcase/shell copilotkit route.
The example's API routes import @copilotkit/runtime/v2 (a server-only package),
but next.config.ts lacked serverExternalPackages, so Next.js attempted to bundle
it. Add serverExternalPackages: ["@copilotkit/runtime"] (base package name covers
the /v2 subpath), mirroring showcase/shell/next.config.ts.
Jordan Ritter
9aac779c51