v0.2.0

• Native build hook (hook/build.dart) using package:hooks and
  package:code_assets — automatically compiles libpackagekit_nc.so via
  CMake at build time and bundles it as a CodeAsset
• Auto-clone sdbus-cpp at pinned commit when submodule is unavailable
  (pub.dev installs)
• Flutter example app (example/packagekit_catalog/) — Material 3 desktop
  catalog with Riverpod state management, GoRouter navigation, search,
  installed packages, updates, and repository views
• Codecov integration with 60% threshold enforcement
• Dart and C++ coverage collection in CI