Phase 3.1 WIP: Riverpod migration (client_app Auth + ChatOpening)

- Add phase3.1 requirement and implementation plan docs
- Add Riverpod dependencies to both client_app and mitra_app
- Wrap both app roots with ProviderScope
- Migrate client_app AuthBloc → AuthNotifier (@riverpod annotation)
- Migrate client_app ChatOpeningBloc → chatPricingProvider (FutureProvider)
- Update router to use Riverpod-based auth state for redirects
- Update all auth screens (display name, register, OTP, force register)
- Update home screen and pricing bottom sheet
- Add android:usesCleartextTraffic for dev HTTP access on both apps
- mitra_app prepared with ProviderScope + ApiClient provider (blocs next)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

client_app/lib/router.dart

@@ -1,7 +1,7 @@
-import 'dart:async';
 import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
-import 'core/auth/auth_bloc.dart';
+import 'core/auth/auth_notifier.dart';
 import 'features/auth/screens/welcome_screen.dart';
 import 'features/auth/screens/display_name_screen.dart';
 import 'features/auth/screens/register_screen.dart';
@@ -16,38 +16,43 @@ import 'features/chat/screens/chat_screen.dart';
 import 'features/chat/screens/chat_history_screen.dart';
 import 'features/chat/screens/chat_transcript_screen.dart';
 
-/// Converts a BLoC stream into a ChangeNotifier for GoRouter's refreshListenable.
-class _BlocRefreshNotifier extends ChangeNotifier {
-  late final StreamSubscription _subscription;
+class RouterNotifier extends ChangeNotifier {
+  final Ref _ref;
 
-  _BlocRefreshNotifier(AuthBloc bloc) {
-    _subscription = bloc.stream.listen((_) => notifyListeners());
-  }
-
-  @override
-  void dispose() {
-    _subscription.cancel();
-    super.dispose();
+  RouterNotifier(this._ref) {
+    _ref.listen(authProvider, (_, __) => notifyListeners());
   }
 }
 
-GoRouter buildRouter(AuthBloc authBloc) {
+final routerProvider = Provider<GoRouter>((ref) => buildRouter(ref));
+
+GoRouter buildRouter(Ref ref) {
+  final notifier = RouterNotifier(ref);
+
   return GoRouter(
     initialLocation: '/splash',
-    refreshListenable: _BlocRefreshNotifier(authBloc),
+    refreshListenable: notifier,
     redirect: (context, state) {
-      final authState = authBloc.state;
+      final authState = ref.read(authProvider);
       final isSplash = state.matchedLocation == '/splash';
       final isAuthRoute = state.matchedLocation.startsWith('/auth') ||
           state.matchedLocation == '/welcome';
 
       // Show splash while loading
-      if (authState is AuthLoading) return isSplash ? null : '/splash';
+      if (authState is AsyncLoading) return isSplash ? null : '/splash';
 
-      if (authState is AuthAuthenticated || authState is AuthAnonymous) {
+      final data = authState.valueOrNull;
+      if (data == null) {
+        // Error state — show login
+        if (!isAuthRoute && !isSplash) return '/welcome';
+        if (isSplash) return '/welcome';
+        return null;
+      }
+
+      if (data is AuthAuthenticatedData || data is AuthAnonymousData) {
         return (isSplash || isAuthRoute) ? '/home' : null;
       }
-      if (authState is AuthForceRegister) return '/auth/force-register';
+      if (data is AuthForceRegisterData) return '/auth/force-register';
       if (!isAuthRoute && !isSplash) return '/welcome';
       if (isSplash) return '/welcome';
       return null;