feat(statistiques): implémentation backend statistiques de progression (ticket #82)

Lots B1+B2+B3 : schéma/domaine, requêtes d'agrégation et ports/use cases pour les statistiques de progression, avec tests associés.

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

test/presentation/home_screen_test.dart

@@ -212,6 +212,10 @@ final class _FakeBootstrap implements AppDependencies {
         repository: _FakeWorkoutHistoryRepository(),
         clock: _FakeClock(DateTime.utc(2026, 7, 17, 12)),
       ),
+      progressionStatsUseCase = ProgressionStatsUseCase(
+        repository: _FakeProgressionStatsRepository(),
+        clock: _FakeClock(DateTime.utc(2026, 7, 17, 12)),
+      ),
       exercisePerformanceReferenceUseCase = ExercisePerformanceReferenceUseCase(
         repository: _FakeExercisePerformanceReferenceRepository(),
       );
@@ -249,6 +253,9 @@ final class _FakeBootstrap implements AppDependencies {
   @override
   final WorkoutHistoryUseCases workoutHistoryUseCases;
 
+  @override
+  final ProgressionStatsUseCase progressionStatsUseCase;
+
   @override
   final ExercisePerformanceReferenceUseCase exercisePerformanceReferenceUseCase;
 }
@@ -711,6 +718,56 @@ final class _FakeWorkoutHistoryRepository implements WorkoutHistoryRepository {
   Future<void> saveStepResult(WorkoutHistoryStepResult result) async {}
 }
 
+final class _FakeProgressionStatsRepository
+    implements ProgressionStatsRepository {
+  @override
+  Future<ProgressionGlobalStatsData> readGlobalStats(
+    ProgressionDateRange range,
+  ) async {
+    return const ProgressionGlobalStatsData(
+      completedSessionCount: 0,
+      totalActiveMs: 0,
+      activeWeekStarts: [],
+      hasAnyCompletedHistory: false,
+    );
+  }
+
+  @override
+  Future<List<ProgressionExerciseOptionData>> listExerciseOptions(
+    ProgressionDateRange range,
+  ) async {
+    return const [];
+  }
+
+  @override
+  Future<List<ProgressionMeasureOptionData>> listMeasureOptions({
+    required ProgressionDateRange range,
+    required String exerciseKey,
+  }) async {
+    return const [];
+  }
+
+  @override
+  Future<ProgressionExerciseSeriesData> readExerciseSeries({
+    required ProgressionDateRange range,
+    required String exerciseKey,
+    required ProgressionMeasure measure,
+  }) async {
+    return ProgressionExerciseSeriesData(
+      exerciseKey: exerciseKey,
+      exerciseNameSnapshot: exerciseKey,
+      measure: ProgressionMeasureOptionData(
+        measure: measure,
+        label: 'Score',
+        lowerIsBetter: false,
+      ),
+      points: const [],
+      hasAnyAllTimeData: false,
+      hasAnyCompletedExerciseResult: false,
+    );
+  }
+}
+
 final class _FakeExercisePerformanceReferenceRepository
     implements ExercisePerformanceReferenceRepository {
   @override