Fetch and read Dart/Flutter package documentation from pub.dev and GitHub. Use when adding a new package dependency, learning how to use a package, checking package version/API, or needing package README documentation. Triggers on: "add package", "use package", "how to use X package", "package docs", "pub.dev", "package documentation", "install package", "flutter pub add", "dart pub add", any mention of integrating or using a specific pub.dev package.