`lib/kernel/src/toolchain.dart` is a `ChangeNotifier`, so it pulls in
`package:flutter/foundation.dart`. `GitClient` and `PqlClient` imported
it for the resolved binary paths, which leaked Flutter through the
`package:clide/clide.dart` barrel — breaking `dart test` on every core
subsystem suite (`ci/test_core.sh`), since pure Dart can't compile
Flutter packages.
Split the Flutter-free pieces into `toolchain_paths.dart`: `ResolvedPaths`,
`resolveToolchainPaths`, and a new read-only `ToolchainView` interface
with a `ToolchainView.resolved()` const factory. `Toolchain` now
implements `ToolchainView`; the clients depend on the interface. Core
test setups that built a `Toolchain` just to call `applyResolved`
switch to the factory.
Co-Authored-By: Claude <noreply@anthropic.com>
jpmschweitzerandClaude
5cad98224f