feat(watch): clôture lot #91 - fréquence cardiaque live, notifications de séance et finitions montre

Consolide le lot applicatif watch companion validé :
- télémétrie fréquence cardiaque live remontée montre -> téléphone
  (collecteur watch, adapter Wear Data Layer, persistance Drift,
  propagation aux écrans historique/programme/profil/exécution)
- notifications de séance en arrière-plan côté téléphone (service
  foreground de statut + passerelle applicative)
- finitions montre : chrono d'étape, score d'étape, retrait du bouton
  "lancer une séance", thème, icônes et polices watch_app

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

lib/domain/entities.dart

@@ -375,6 +375,11 @@ final class Exercise {
       defaultTargetScoreTimeMs,
       'Default target score time ms',
     );
+    _requireLinkedStepSeriesScoreShape(
+      steps: steps,
+      scoreEnabled: hasScoreMeasure,
+      scoreInputMode: scoreInputMode,
+    );
   }
 
   final EntityMetadata metadata;
@@ -508,6 +513,7 @@ final class ExerciseStep {
     this.scoreUnit,
     this.defaultTargetScore,
     this.defaultTargetScoreTimeMs,
+    this.linkedToSeriesScore = false,
   }) : id = _nonBlank(id, 'Exercise step id'),
        name = _nonBlank(name, 'Exercise step name') {
     _requireNonNegative(position, 'Exercise step position');
@@ -519,6 +525,7 @@ final class ExerciseStep {
       scoreUnit: scoreUnit,
       defaultTargetScore: defaultTargetScore,
       defaultTargetScoreTimeMs: defaultTargetScoreTimeMs,
+      linkedToSeriesScore: linkedToSeriesScore,
     );
   }
 
@@ -533,6 +540,7 @@ final class ExerciseStep {
   final String? scoreUnit;
   final double? defaultTargetScore;
   final int? defaultTargetScoreTimeMs;
+  final bool linkedToSeriesScore;
 
   Map<String, Object?> toSnapshotJson() => {
     'id': id,
@@ -546,6 +554,7 @@ final class ExerciseStep {
     'scoreUnit': scoreUnit,
     'defaultTargetScore': defaultTargetScore,
     'defaultTargetScoreTimeMs': defaultTargetScoreTimeMs,
+    'linkedToSeriesScore': linkedToSeriesScore,
   };
 }
 
@@ -658,6 +667,11 @@ final class ProgramExercise {
       targetScore: targetScore,
       targetScoreTimeMs: targetScoreTimeMs,
     );
+    _requireLinkedStepSeriesScoreShape(
+      steps: exerciseStepsSnapshot,
+      scoreEnabled: scoreEnabled,
+      scoreInputMode: scoreInputModeSnapshot,
+    );
   }
 
   final EntityMetadata metadata;
@@ -1100,6 +1114,47 @@ final class ActiveScoreStopwatchState {
   }
 }
 
+final class ActiveManualScoreState {
+  ActiveManualScoreState({
+    required this.metadata,
+    required this.activeWorkoutSessionId,
+    required this.programIndex,
+    required this.exerciseIndex,
+    required this.setIndex,
+    required this.value,
+    required this.updatedAt,
+  }) {
+    _requireNonNegative(programIndex, 'Program index');
+    _requireNonNegative(exerciseIndex, 'Exercise index');
+    _requireNonNegative(setIndex, 'Set index');
+    _requireNullableNonNegativeDouble(value, 'Manual score value');
+  }
+
+  final EntityMetadata metadata;
+  final String activeWorkoutSessionId;
+  final int programIndex;
+  final int exerciseIndex;
+  final int setIndex;
+  final double value;
+  final DateTime updatedAt;
+
+  ActiveManualScoreState copyWith({
+    EntityMetadata? metadata,
+    double? value,
+    DateTime? updatedAt,
+  }) {
+    return ActiveManualScoreState(
+      metadata: metadata ?? this.metadata,
+      activeWorkoutSessionId: activeWorkoutSessionId,
+      programIndex: programIndex,
+      exerciseIndex: exerciseIndex,
+      setIndex: setIndex,
+      value: value ?? this.value,
+      updatedAt: updatedAt ?? this.updatedAt,
+    );
+  }
+}
+
 final class ActiveSetTimerState {
   ActiveSetTimerState({
     required this.metadata,
@@ -1405,7 +1460,7 @@ final class ActiveExerciseStepResult {
 }
 
 final class WorkoutHistory {
-  const WorkoutHistory({
+  WorkoutHistory({
     required this.metadata,
     this.sourceWorkoutTemplateId,
     this.sourceActiveWorkoutSessionId,
@@ -1415,9 +1470,17 @@ final class WorkoutHistory {
     required this.totalActiveMs,
     required this.completed,
     required this.historySnapshotJson,
+    this.averageHeartRateBpm,
+    this.maxHeartRateBpm,
     this.results = const [],
     this.stepResults = const [],
-  });
+  }) {
+    _requireNullablePositiveDouble(
+      averageHeartRateBpm,
+      'Average heart rate bpm',
+    );
+    _requireNullablePositive(maxHeartRateBpm, 'Max heart rate bpm');
+  }
 
   final EntityMetadata metadata;
   final String? sourceWorkoutTemplateId;
@@ -1428,8 +1491,36 @@ final class WorkoutHistory {
   final int totalActiveMs;
   final bool completed;
   final String historySnapshotJson;
+  final double? averageHeartRateBpm;
+  final int? maxHeartRateBpm;
   final List<WorkoutHistorySetResult> results;
   final List<WorkoutHistoryStepResult> stepResults;
+
+  WorkoutHistory copyWith({
+    EntityMetadata? metadata,
+    Object? averageHeartRateBpm = _unchanged,
+    Object? maxHeartRateBpm = _unchanged,
+  }) {
+    return WorkoutHistory(
+      metadata: metadata ?? this.metadata,
+      sourceWorkoutTemplateId: sourceWorkoutTemplateId,
+      sourceActiveWorkoutSessionId: sourceActiveWorkoutSessionId,
+      nameSnapshot: nameSnapshot,
+      startedAt: startedAt,
+      endedAt: endedAt,
+      totalActiveMs: totalActiveMs,
+      completed: completed,
+      historySnapshotJson: historySnapshotJson,
+      averageHeartRateBpm: averageHeartRateBpm == _unchanged
+          ? this.averageHeartRateBpm
+          : averageHeartRateBpm as double?,
+      maxHeartRateBpm: maxHeartRateBpm == _unchanged
+          ? this.maxHeartRateBpm
+          : maxHeartRateBpm as int?,
+      results: results,
+      stepResults: stepResults,
+    );
+  }
 }
 
 final class WorkoutHistorySetResult {
@@ -1721,6 +1812,12 @@ void _requireNullableNonNegativeDouble(double? value, String label) {
   }
 }
 
+void _requireNullablePositiveDouble(double? value, String label) {
+  if (value != null && value <= 0) {
+    throw DomainException('$label must be positive.');
+  }
+}
+
 void _requireScoreTargetShape({
   required bool scoreEnabled,
   required ScoreInputMode scoreInputMode,
@@ -1753,12 +1850,14 @@ void _validateExerciseStepScoreShape({
   required String? scoreUnit,
   required double? defaultTargetScore,
   required int? defaultTargetScoreTimeMs,
+  required bool linkedToSeriesScore,
 }) {
   if (!hasScore) {
     if (scoreLabel != null ||
         scoreUnit != null ||
         defaultTargetScore != null ||
-        defaultTargetScoreTimeMs != null) {
+        defaultTargetScoreTimeMs != null ||
+        linkedToSeriesScore) {
       throw const DomainException(
         'Disabled exercise step score must not define score values.',
       );
@@ -1784,6 +1883,11 @@ void _validateExerciseStepScoreShape({
         );
       }
     case ScoreInputMode.stopwatch:
+      if (linkedToSeriesScore) {
+        throw const DomainException(
+          'Linked series score requires manual exercise step score.',
+        );
+      }
       if (scoreLabel != null ||
           scoreUnit != null ||
           defaultTargetScore != null) {
@@ -1820,6 +1924,19 @@ void _requireScoreResultShape({
   }
 }
 
+void _requireLinkedStepSeriesScoreShape({
+  required List<ExerciseStep> steps,
+  required bool scoreEnabled,
+  required ScoreInputMode scoreInputMode,
+}) {
+  if (steps.any((step) => step.linkedToSeriesScore) &&
+      (!scoreEnabled || scoreInputMode != ScoreInputMode.manual)) {
+    throw const DomainException(
+      'Linked step scores require manual series score.',
+    );
+  }
+}
+
 void _validateExerciseStepResult({
   required int programIndex,
   required int exerciseIndex,