Phase 3 testing fixes: Fastify 5, SSE→WebSocket+FCM, enums, security, session lifecycle

- Upgrade Fastify 4→5 with all plugins (@fastify/websocket 11, cors 11, sensible 6)
- Migrate all SSE endpoints to WebSocket + FCM push (mitra chat requests, customer pairing status)
- Add flutter_local_notifications for foreground push notifications with sound
- Add splash screen to both apps (hide auth loading flash)
- Introduce constants/enums across entire codebase (no raw string literals)
- Move price tiers from hardcoded array to app_config DB (data-driven, includes 1-min test tier)
- Add session ownership validation on all shared chat routes
- Add ownership checks on endSession, respondToExtension, requestExtension
- Fix session timer: auto-complete expired/stale sessions on server restart
- Add 5-min grace period for abandoned closing sessions
- Fix extension flow: proper session_resumed handling, clearExtensionRequest, closure grace timer cleanup
- Fix chat screens: ConnectChat in initState, session status check on connect
- Fix customer expired view: 5-min countdown, closure state priority over expired state
- Fix mitra extension UI: loading spinner, disable buttons, handle EXTENSION_RESOLVED error
- Fix GoRouter navigation consistency (no more Navigator.pushNamed)
- Fix goodbye view keyboard overflow (SingleChildScrollView)
- Add active session card on customer home screen with refresh on navigate back
- Fix PricingBottomSheet extension mode (RequestExtension instead of new pairing)
- Send session_resumed to both parties on extension accept

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

client_app/lib/features/home/home_screen.dart

@@ -2,12 +2,64 @@ import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:go_router/go_router.dart';
 import '../../core/auth/auth_bloc.dart';
+import '../../core/api/api_client.dart';
 import '../../core/pairing/pairing_bloc.dart';
 import '../chat/widgets/pricing_bottom_sheet.dart';
 
-class HomeScreen extends StatelessWidget {
+class HomeScreen extends StatefulWidget {
   const HomeScreen({super.key});
 
+  @override
+  State<HomeScreen> createState() => _HomeScreenState();
+}
+
+class _HomeScreenState extends State<HomeScreen> with WidgetsBindingObserver {
+  Map<String, dynamic>? _activeSession;
+  bool _loadingSession = true;
+
+  @override
+  void initState() {
+    super.initState();
+    WidgetsBinding.instance.addObserver(this);
+    _checkActiveSession();
+  }
+
+  @override
+  void dispose() {
+    WidgetsBinding.instance.removeObserver(this);
+    super.dispose();
+  }
+
+  @override
+  void didChangeAppLifecycleState(AppLifecycleState state) {
+    if (state == AppLifecycleState.resumed) {
+      _checkActiveSession();
+    }
+  }
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    // Re-check when navigating back to this screen
+    _checkActiveSession();
+  }
+
+  Future<void> _checkActiveSession() async {
+    try {
+      final apiClient = context.read<ApiClient>();
+      final response = await apiClient.get('/api/client/chat/session/active');
+      final data = response['data'];
+      if (mounted) {
+        setState(() {
+          _activeSession = data is Map<String, dynamic> ? data : null;
+          _loadingSession = false;
+        });
+      }
+    } catch (_) {
+      if (mounted) setState(() => _loadingSession = false);
+    }
+  }
+
   @override
   Widget build(BuildContext context) {
     return BlocListener<PairingBloc, PairingState>(
@@ -51,14 +103,28 @@ class HomeScreen extends StatelessWidget {
                   mainAxisAlignment: MainAxisAlignment.center,
                   children: [
                     Text('Halo, $displayName!', style: const TextStyle(fontSize: 24)),
-                    const SizedBox(height: 48),
-                    ElevatedButton(
-                      style: ElevatedButton.styleFrom(
-                        padding: const EdgeInsets.symmetric(horizontal: 48, vertical: 16),
+                    const SizedBox(height: 32),
+                    if (_loadingSession)
+                      const CircularProgressIndicator()
+                    else if (_activeSession != null)
+                      _ActiveSessionCard(
+                        session: _activeSession!,
+                        onTap: () {
+                          final sessionId = _activeSession!['id'] as String;
+                          final mitraName = _activeSession!['mitra_display_name'] as String? ?? 'Bestie';
+                          context.push('/chat/session/$sessionId', extra: mitraName);
+                        },
+                      )
+                    else ...[
+                      const SizedBox(height: 16),
+                      ElevatedButton(
+                        style: ElevatedButton.styleFrom(
+                          padding: const EdgeInsets.symmetric(horizontal: 48, vertical: 16),
+                        ),
+                        onPressed: () => PricingBottomSheet.show(context),
+                        child: const Text('Mulai Curhat', style: TextStyle(fontSize: 18)),
                       ),
-                      onPressed: () => PricingBottomSheet.show(context),
-                      child: const Text('Mulai Curhat', style: TextStyle(fontSize: 18)),
-                    ),
+                    ],
                   ],
                 ),
               ),
@@ -69,3 +135,52 @@ class HomeScreen extends StatelessWidget {
     );
   }
 }
+
+class _ActiveSessionCard extends StatelessWidget {
+  final Map<String, dynamic> session;
+  final VoidCallback onTap;
+
+  const _ActiveSessionCard({required this.session, required this.onTap});
+
+  @override
+  Widget build(BuildContext context) {
+    final mitraName = session['mitra_display_name'] as String? ?? 'Bestie';
+
+    return Card(
+      elevation: 2,
+      child: InkWell(
+        onTap: onTap,
+        borderRadius: BorderRadius.circular(12),
+        child: Padding(
+          padding: const EdgeInsets.all(20),
+          child: Row(
+            children: [
+              const CircleAvatar(
+                backgroundColor: Colors.green,
+                child: Icon(Icons.chat, color: Colors.white),
+              ),
+              const SizedBox(width: 16),
+              Expanded(
+                child: Column(
+                  crossAxisAlignment: CrossAxisAlignment.start,
+                  children: [
+                    const Text(
+                      'Sesi Aktif',
+                      style: TextStyle(fontSize: 16, fontWeight: FontWeight.bold),
+                    ),
+                    const SizedBox(height: 4),
+                    Text(
+                      'Sedang curhat dengan $mitraName',
+                      style: const TextStyle(fontSize: 14, color: Colors.grey),
+                    ),
+                  ],
+                ),
+              ),
+              const Icon(Icons.chevron_right),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}