Phase 2 scaffold: mitra online status & pairing logic

Add mitra online/offline status with heartbeat-based auto-offline,
customer-mitra pairing via Valkey pub/sub blast, session management,
and control center dashboard with real-time stats.

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

client_app/lib/router.dart

@@ -7,6 +7,10 @@ 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';
+import 'features/chat/screens/searching_screen.dart';
+import 'features/chat/screens/bestie_found_screen.dart';
+import 'features/chat/screens/no_bestie_screen.dart';
+import 'features/chat/screens/session_active_screen.dart';
 
 GoRouter buildRouter(AuthBloc authBloc) {
   return GoRouter(
@@ -30,6 +34,21 @@ GoRouter buildRouter(AuthBloc authBloc) {
       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()),
+      GoRoute(path: '/chat/searching', builder: (_, __) => const SearchingScreen()),
+      GoRoute(path: '/chat/found', builder: (context, state) {
+        final extra = state.extra as Map<String, dynamic>;
+        return BestieFoundScreen(
+          sessionId: extra['sessionId'] as String,
+          mitraName: extra['mitraName'] as String,
+        );
+      }),
+      GoRoute(path: '/chat/no-bestie', builder: (_, __) => const NoBestieScreen()),
+      GoRoute(path: '/chat/session/:sessionId', builder: (context, state) {
+        return SessionActiveScreen(
+          sessionId: state.pathParameters['sessionId']!,
+          mitraName: state.extra as String? ?? 'Bestie',
+        );
+      }),
     ],
   );
 }