fix(ui): bandeau de reprise de séance en cours (ticket #32)

Ajoute/corrige le bandeau de reprise sur home_screen.dart, avec les
ajustements de bootstrap applicatif nécessaires, et sa couverture de
tests. flutter analyze propre, 45/45 tests verts, build APK debug
validé. Ticket laissé en QA : validation manuelle sur APK par
l'utilisateur avant clôture.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

lib/presentation/home_screen.dart

@@ -9,6 +9,8 @@ import 'theme.dart';
 import 'workout_execution_screen.dart';
 import 'workout_template_screen.dart';
 
+final homeRouteObserver = RouteObserver<ModalRoute<void>>();
+
 final class HomeScreen extends StatefulWidget {
   const HomeScreen({
     required this.bootstrap,
@@ -17,7 +19,7 @@ final class HomeScreen extends StatefulWidget {
     super.key,
   });
 
-  final AppBootstrap bootstrap;
+  final AppDependencies bootstrap;
   final ThemeMode themeMode;
   final ValueChanged<ThemeMode>? onThemeModeChanged;
 
@@ -25,13 +27,40 @@ final class HomeScreen extends StatefulWidget {
   State<HomeScreen> createState() => _HomeScreenState();
 }
 
-final class _HomeScreenState extends State<HomeScreen> {
+final class _HomeScreenState extends State<HomeScreen> with RouteAware {
   late Future<ActiveWorkoutSession?> _openSession;
+  ModalRoute<void>? _route;
 
   @override
   void initState() {
     super.initState();
-    _openSession = widget.bootstrap.activeWorkoutSessionUseCases.findOpen();
+    _openSession = _findOpenSession();
+  }
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    final route = ModalRoute.of<void>(context);
+    if (route == null || identical(route, _route)) {
+      return;
+    }
+    final previousRoute = _route;
+    if (previousRoute != null) {
+      homeRouteObserver.unsubscribe(this);
+    }
+    _route = route;
+    homeRouteObserver.subscribe(this, route);
+  }
+
+  @override
+  void dispose() {
+    homeRouteObserver.unsubscribe(this);
+    super.dispose();
+  }
+
+  @override
+  void didPopNext() {
+    _reloadOpenSession();
   }
 
   @override
@@ -163,8 +192,16 @@ final class _HomeScreenState extends State<HomeScreen> {
       ),
     );
     if (!mounted) return;
+    _reloadOpenSession();
+  }
+
+  Future<ActiveWorkoutSession?> _findOpenSession() {
+    return widget.bootstrap.activeWorkoutSessionUseCases.findOpen();
+  }
+
+  void _reloadOpenSession() {
     setState(() {
-      _openSession = widget.bootstrap.activeWorkoutSessionUseCases.findOpen();
+      _openSession = _findOpenSession();
     });
   }
 }