Firebase Setup

• Use firebase_core for initialization — call Firebase.initializeApp() before runApp()
• Use flutterfire configure for platform-specific setup
• Use separate Firebase projects per flavor (see app-config skill)
• Register Firebase services via injectable for consistent DI

Authentication

• Use firebase_auth for user management
• Wrap all auth calls in an AuthRepository — no direct FirebaseAuth usage in BLoCs or UI
• Support email/password, Google Sign-In, and Apple Sign-In at minimum
• Handle auth state changes via FirebaseAuth.instance.authStateChanges() stream in AuthBloc
• Store auth tokens via flutter_secure_storage — never in SharedPreferences or source code
• Implement proper sign-out: clear local cache, navigate to login, dispose user-specific BLoCs

Firestore