Numanshakir/flutter_base_app ? reverse-engineered prompt

Build me the Flutter monorepo app described here, with a clean starter experience for mobile and web.

I want the main app wired up with Riverpod state management, GoRouter navigation, and a simple auth aware flow where unauthenticated users get sent to sign in. Set it up so the app boots through a shared startup wrapper, uses a Material 3 theme, and has a solid base for adding more screens later. Please keep the shared UI bits, helpers, and services in a reusable package, and keep the data and network layer in a separate core package with environment based API setup, Dio, interceptors, and the usual code generation pieces for models and API calls.

Make sure the workspace structure works from the repo root, the web URL strategy is clean, and the generated code setup is ready to go. If anything is unclear, look up the current Flutter and package docs online and then wire it up in a way that feels production ready but still easy to extend.