Installation for simple-chatapp fails due to package-lock.json pointing to internal Anthropic resources

**What happened**: The package-lock.json file had hardcoded URLs pointing to Anthropic's internal Artifactory server (artifactory.infra.ant.dev). This likely happened because someone at Anthropic created the lockfile while connected to their internal registry. When you tried to install, npm tried to use those URLs, which require authentication you don't have.

**The fix**: Deleting the lockfile and running npm install regenerated it using the public npm registry.