feat(ui): écran Bibliothèque d'exercices

Ajoute l'écran de bibliothèque d'exercices (presentation/exercise_library_screen.dart)
et ajuste la couche application/domaine (bootstrap, ports, use cases,
entités, repositories Drift) pour l'alimenter. flutter analyze propre,
9/9 tests verts, build APK debug validé.

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

lib/application/app_bootstrap.dart

@@ -1,15 +1,43 @@
-import '../infrastructure/local/app_database.dart';
+import '../infrastructure/local/local.dart';
+import 'application.dart';
 
 final class AppBootstrap {
-  AppBootstrap._({required this.database});
+  AppBootstrap._({
+    required this.database,
+    required this.exerciseUseCases,
+    required this.mediaUseCases,
+  });
 
   final AppDatabase database;
+  final ExerciseUseCases exerciseUseCases;
+  final MediaUseCases mediaUseCases;
 
   static Future<AppBootstrap> create() async {
     final database = AppDatabase.open();
     await database.customSelect('SELECT 1').get();
+    final exerciseRepository = DriftExerciseRepository(database);
+    final mediaRepository = DriftMediaAssetRepository(database);
+    final ids = LocalIdGenerator();
+    const clock = SystemClock();
+    const originDeviceId = 'local-device';
 
-    return AppBootstrap._(database: database);
+    return AppBootstrap._(
+      database: database,
+      exerciseUseCases: ExerciseUseCases(
+        repository: exerciseRepository,
+        clock: clock,
+        ids: ids,
+        originDeviceId: originDeviceId,
+      ),
+      mediaUseCases: MediaUseCases(
+        mediaRepository: mediaRepository,
+        exerciseRepository: exerciseRepository,
+        storage: const PathProviderLocalMediaStorage(),
+        clock: clock,
+        ids: ids,
+        originDeviceId: originDeviceId,
+      ),
+    );
   }
 
   Future<void> dispose() => database.close();

lib/application/ports.dart

@@ -18,6 +18,7 @@ abstract interface class IdGenerator {
 abstract interface class ExerciseRepository {
   Future<Exercise?> findById(String id);
   Future<List<Exercise>> listActive();
+  Future<bool> isReferencedByProgram(String id);
   Future<void> save(Exercise exercise);
 }
 

lib/application/use_cases.dart

@@ -46,6 +46,44 @@ final class ExerciseUseCases {
 
   Future<void> save(Exercise exercise) => repository.save(exercise);
 
+  Future<List<Exercise>> listActive() => repository.listActive();
+
+  Future<bool> isUsedInPrograms(String id) {
+    return repository.isReferencedByProgram(id);
+  }
+
+  Future<Exercise> update({
+    required String id,
+    required String name,
+    String? description,
+    String? imageMediaId,
+    String? videoMediaId,
+    required bool hasTimeMeasure,
+    required bool hasRepsMeasure,
+    required bool hasScoreMeasure,
+    String? scoreLabel,
+    String? scoreUnit,
+  }) async {
+    final exercise = await repository.findById(id);
+    if (exercise == null) {
+      throw const DomainException('Exercise not found.');
+    }
+    final updated = exercise.copyWith(
+      metadata: exercise.metadata.touch(clock.now()),
+      name: name,
+      description: description,
+      imageMediaId: imageMediaId,
+      videoMediaId: videoMediaId,
+      hasTimeMeasure: hasTimeMeasure,
+      hasRepsMeasure: hasRepsMeasure,
+      hasScoreMeasure: hasScoreMeasure,
+      scoreLabel: scoreLabel,
+      scoreUnit: scoreUnit,
+    );
+    await repository.save(updated);
+    return updated;
+  }
+
   Future<Exercise> attachImage({
     required String exerciseId,
     required String mediaAssetId,