Migrate from Cargokit to Native Assets

Native Assets changes how the Rust library is built and bundled; the Rust and Dart APIs stay unchanged.

Migrate

1. Run the integration command from the Flutter package root:

   flutter_rust_bridge_codegen integrate --integration-backend native-assets

2. Check the generated hook/build.dart and the Rust crate requirements.

3. Remove the old Cargokit integration:

   • Apps: Remove rust_builder/, its pubspec.yaml path dependency, and its analysis_options.yaml exclusion.
   • Packages: Remove cargokit/ and the Flutter plugin entries used only by the old ffiPlugin scaffold.

4. Refresh dependencies and regenerate the bridge:

   flutter pub get
   flutter_rust_bridge_codegen generate

Keep the Rust crate, generated bridge code, and your own Dart and Rust code. Test every platform supported by the project after migrating.