Wires every side effect and native channel as an injectable interface behind a Provider that throws UnimplementedError until the composition root overrides it, with one live impl per flavor, value-typed signatures returning typed results, hand-written contract-honouring fakes over mocks, MethodChannel quarantined to one lib/native/ directory, and versioned cross-language contracts edited on both sides in one commit. Use when adding or changing a ShareService/AnalyticsService/RemoteConfigService or any side-effect port, injecting a Clock (package:clock) via clockProvider, a MethodChannel/platform channel or native widget bridge, a flavor entrypoint (main_*.dart) or per-fla…
