Phase 1 scaffold: auth for all apps

- Backend: Fastify with two listeners (public + internal), routes, services, DB migration + seed
- client_app: Flutter with BLoC, all auth screens (welcome, display name, register, OTP, force-register)
- mitra_app: Flutter with BLoC, OTP-only login
- control_center: React + Vite, email/password login, mitra/user management, anonymity settings
- Docs: phase1 plan, API contract, client app mockup
- CLAUDE.md and shared memory for all subprojects

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

client_app/lib/router.dart

@@ -0,0 +1,35 @@
+import 'package:flutter/material.dart';
+import 'package:go_router/go_router.dart';
+import 'core/auth/auth_bloc.dart';
+import 'features/auth/screens/welcome_screen.dart';
+import 'features/auth/screens/display_name_screen.dart';
+import 'features/auth/screens/register_screen.dart';
+import 'features/auth/screens/otp_screen.dart';
+import 'features/auth/screens/force_register_screen.dart';
+import 'features/home/home_screen.dart';
+
+GoRouter buildRouter(AuthBloc authBloc) {
+  return GoRouter(
+    initialLocation: '/welcome',
+    redirect: (context, state) {
+      final authState = authBloc.state;
+      final isAuthRoute = state.matchedLocation.startsWith('/auth') ||
+          state.matchedLocation == '/welcome';
+
+      if (authState is AuthAuthenticated || authState is AuthAnonymous) {
+        return isAuthRoute ? '/home' : null;
+      }
+      if (authState is AuthForceRegister) return '/auth/force-register';
+      if (!isAuthRoute) return '/welcome';
+      return null;
+    },
+    routes: [
+      GoRoute(path: '/welcome', builder: (_, __) => const WelcomeScreen()),
+      GoRoute(path: '/auth/display-name', builder: (_, __) => const DisplayNameScreen()),
+      GoRoute(path: '/auth/register', builder: (_, __) => const RegisterScreen()),
+      GoRoute(path: '/auth/otp', builder: (context, state) => OtpScreen(phone: state.extra as String)),
+      GoRoute(path: '/auth/force-register', builder: (_, __) => const ForceRegisterScreen()),
+      GoRoute(path: '/home', builder: (_, __) => const HomeScreen()),
+    ],
+  );
+}