fix(programme): étapes d'exercice jamais affichées en séance (ticket #72)

_ProgramExerciseDraft dans program_screen.dart (état interne du
formulaire de composition de programme) n'avait jamais de champ
exerciseStepsSnapshot depuis sa création, avant le chantier "Exercice
à plusieurs étapes" (#54). Les étapes d'un exercice étaient donc
systématiquement perdues à chaque composition/édition de programme
via l'écran réel, peu importe l'ordre des opérations — d'où l'absence
totale d'étapes affichées en séance. Ajoute le champ manquant et 2
tests de non-régression exerçant le vrai flux UI ProgramFormScreen.
flutter pub get OK, dart format appliqué (aucun changement), analyze
propre (mêmes infos préexistantes), 135/135 tests verts, build APK
debug validé.

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

lib/presentation/program_screen.dart

@@ -915,6 +915,7 @@ final class _ProgramExerciseDraft {
     this.exerciseImageMediaIdSnapshot,
     this.exerciseImageMediaIdsSnapshot = const [],
     this.exerciseVideoMediaIdSnapshot,
+    this.exerciseStepsSnapshot = const [],
     this.exerciseArchivedSnapshot = false,
     required this.availableTimeSnapshot,
     required this.availableRepsSnapshot,
@@ -944,6 +945,7 @@ final class _ProgramExerciseDraft {
           exercise.iconMediaId ?? exercise.imageMediaId,
       exerciseImageMediaIdsSnapshot: exercise.imageMediaIds,
       exerciseVideoMediaIdSnapshot: exercise.videoMediaId,
+      exerciseStepsSnapshot: exercise.steps,
       exerciseArchivedSnapshot: exercise.archivedAt != null,
       availableTimeSnapshot: exercise.hasTimeMeasure,
       availableRepsSnapshot: exercise.hasRepsMeasure,
@@ -975,6 +977,7 @@ final class _ProgramExerciseDraft {
       exerciseImageMediaIdSnapshot: exercise.exerciseImageMediaIdSnapshot,
       exerciseImageMediaIdsSnapshot: exercise.exerciseImageMediaIdsSnapshot,
       exerciseVideoMediaIdSnapshot: exercise.exerciseVideoMediaIdSnapshot,
+      exerciseStepsSnapshot: exercise.exerciseStepsSnapshot,
       exerciseArchivedSnapshot: exercise.exerciseArchivedSnapshot,
       availableTimeSnapshot: exercise.availableTimeSnapshot,
       availableRepsSnapshot: exercise.availableRepsSnapshot,
@@ -1004,6 +1007,7 @@ final class _ProgramExerciseDraft {
   final String? exerciseImageMediaIdSnapshot;
   final List<String> exerciseImageMediaIdsSnapshot;
   final String? exerciseVideoMediaIdSnapshot;
+  final List<ExerciseStep> exerciseStepsSnapshot;
   final bool exerciseArchivedSnapshot;
   final bool availableTimeSnapshot;
   final bool availableRepsSnapshot;
@@ -1029,6 +1033,7 @@ final class _ProgramExerciseDraft {
       exerciseImageMediaIdSnapshot: exerciseImageMediaIdSnapshot,
       exerciseImageMediaIdsSnapshot: exerciseImageMediaIdsSnapshot,
       exerciseVideoMediaIdSnapshot: exerciseVideoMediaIdSnapshot,
+      exerciseStepsSnapshot: exerciseStepsSnapshot,
       exerciseArchivedSnapshot: exerciseArchivedSnapshot,
       availableTimeSnapshot: availableTimeSnapshot,
       availableRepsSnapshot: availableRepsSnapshot,
@@ -1057,6 +1062,7 @@ final class _ProgramExerciseDraft {
       exerciseImageMediaIdSnapshot: exerciseImageMediaIdSnapshot,
       exerciseImageMediaIdsSnapshot: exerciseImageMediaIdsSnapshot,
       exerciseVideoMediaIdSnapshot: exerciseVideoMediaIdSnapshot,
+      exerciseStepsSnapshot: exerciseStepsSnapshot,
       exerciseArchivedSnapshot: exerciseArchivedSnapshot,
       availableTimeSnapshot: availableTimeSnapshot,
       availableRepsSnapshot: availableRepsSnapshot,

test/presentation/program_screen_test.dart

@@ -164,6 +164,148 @@ void main() {
     },
   );
 
+  testWidgets(
+    'ajouter un exercice avec étapes conserve le snapshot des étapes',
+    (tester) async {
+      final steps = [
+        _step(
+          id: 'step-1',
+          position: 0,
+          name: 'Course',
+          type: ExerciseStepType.time,
+        ),
+        _step(
+          id: 'step-2',
+          position: 1,
+          name: 'Tirs',
+          type: ExerciseStepType.reps,
+        ),
+      ];
+      final programRepository = _FakeProgramRepository();
+      final exerciseRepository = _FakeExerciseRepository()
+        ..exercises.add(
+          Exercise(
+            metadata: _metadata('exercise-steps'),
+            name: 'Circuit tirs',
+            hasTimeMeasure: false,
+            hasRepsMeasure: true,
+            hasScoreMeasure: false,
+            defaultTargetReps: 2,
+            steps: steps,
+          ),
+        );
+
+      await tester.pumpWidget(
+        MaterialApp(
+          home: ProgramFormScreen(
+            programUseCases: _programUseCases(
+              programRepository,
+              exerciseRepository,
+            ),
+            exerciseUseCases: _exerciseUseCases(exerciseRepository),
+          ),
+        ),
+      );
+
+      await tester.enterText(
+        find.widgetWithText(TextFormField, 'Nom'),
+        'Programme étapes',
+      );
+      await tester.tap(find.text('Ajouter un exercice'));
+      await tester.pumpAndSettle();
+      await tester.tap(find.text('Circuit tirs'));
+      await tester.pumpAndSettle();
+      await tester.tap(find.text('Enregistrer'));
+      await tester.pumpAndSettle();
+
+      final savedSteps = programRepository
+          .programs
+          .single
+          .exercises
+          .single
+          .exerciseStepsSnapshot;
+      expect(savedSteps, hasLength(2));
+      expect(savedSteps.map((step) => step.name), ['Course', 'Tirs']);
+      expect(savedSteps.map((step) => step.type), [
+        ExerciseStepType.time,
+        ExerciseStepType.reps,
+      ]);
+    },
+  );
+
+  testWidgets(
+    'réenregistrer un programme existant conserve les étapes du snapshot',
+    (tester) async {
+      final steps = [
+        _step(
+          id: 'step-1',
+          position: 0,
+          name: 'Course',
+          type: ExerciseStepType.time,
+        ),
+        _step(
+          id: 'step-2',
+          position: 1,
+          name: 'Tirs',
+          type: ExerciseStepType.reps,
+        ),
+      ];
+      final programRepository = _FakeProgramRepository()
+        ..programs.add(
+          Program(
+            metadata: _metadata('program-steps'),
+            name: 'Programme étapes',
+            defaultRestSeconds: 45,
+            exercises: [
+              ProgramExercise(
+                metadata: _metadata('program-exercise-steps'),
+                programId: 'program-steps',
+                sourceExerciseId: 'exercise-steps',
+                position: 0,
+                exerciseNameSnapshot: 'Circuit tirs',
+                exerciseStepsSnapshot: steps,
+                availableTimeSnapshot: false,
+                availableRepsSnapshot: true,
+                availableScoreSnapshot: false,
+                setsCount: 3,
+                timeEnabled: false,
+                repsEnabled: true,
+                scoreEnabled: false,
+                targetReps: 2,
+              ),
+            ],
+          ),
+        );
+      final exerciseRepository = _FakeExerciseRepository();
+
+      await tester.pumpWidget(
+        MaterialApp(
+          home: ProgramFormScreen(
+            programUseCases: _programUseCases(
+              programRepository,
+              exerciseRepository,
+            ),
+            exerciseUseCases: _exerciseUseCases(exerciseRepository),
+            program: programRepository.programs.single,
+          ),
+        ),
+      );
+
+      await tester.tap(find.text('Enregistrer'));
+      await tester.pumpAndSettle();
+
+      final savedSteps = programRepository
+          .programs
+          .single
+          .exercises
+          .single
+          .exerciseStepsSnapshot;
+      expect(savedSteps, hasLength(2));
+      expect(savedSteps.map((step) => step.name), ['Course', 'Tirs']);
+      expect(savedSteps.map((step) => step.position), [0, 1]);
+    },
+  );
+
   testWidgets('affiche l’objectif de chrono pour un score en mode chrono', (
     tester,
   ) async {
@@ -510,6 +652,21 @@ EntityMetadata _metadata(String id) {
   );
 }
 
+ExerciseStep _step({
+  required String id,
+  required int position,
+  required String name,
+  required ExerciseStepType type,
+}) {
+  return ExerciseStep(
+    id: id,
+    position: position,
+    name: name,
+    type: type,
+    defaultTargetValue: type == ExerciseStepType.time ? 30 : 5,
+  );
+}
+
 final class _FakeClock implements Clock {
   const _FakeClock(this.value);