fix(execution): reprise en temps réel de la séance en cours (ticket #14)

Corrige la reprise de séance sur workout_execution_screen.dart suite
aux retours de QA. flutter analyze propre, 26/26 tests verts, build
APK debug validé.

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

lib/presentation/workout_execution_screen.dart

@@ -36,6 +36,8 @@ final class _WorkoutExecutionScreenState extends State<WorkoutExecutionScreen> {
   Timer? _ticker;
   Timer? _restTicker;
   WorkoutHistory? _completedHistory;
+  String? _activeRestStateId;
+  late DateTime _seriesStartedAt;
   var _reps = 0;
   final _scoreController = TextEditingController();
   var _remainingRestSeconds = 0;
@@ -56,9 +58,11 @@ final class _WorkoutExecutionScreenState extends State<WorkoutExecutionScreen> {
     _mode = _session.status == ActiveWorkoutStatus.running
         ? WorkoutExecutionMode.active
         : WorkoutExecutionMode.paused;
+    _seriesStartedAt = DateTime.now().toUtc();
     _ticker = Timer.periodic(const Duration(seconds: 1), (_) {
       if (mounted) setState(() {});
     });
+    unawaited(_restoreActiveRest());
   }
 
   @override
@@ -158,20 +162,14 @@ final class _WorkoutExecutionScreenState extends State<WorkoutExecutionScreen> {
             children: [
               Expanded(
                 child: OutlinedButton(
-                  onPressed: () => setState(() {
-                    _remainingRestSeconds = (_remainingRestSeconds - 15)
-                        .clamp(0, 9999)
-                        .toInt();
-                  }),
+                  onPressed: () => _adjustRest(-15),
                   child: const Text('-15 s'),
                 ),
               ),
               const SizedBox(width: 12),
               Expanded(
                 child: OutlinedButton(
-                  onPressed: () => setState(() {
-                    _remainingRestSeconds += 15;
-                  }),
+                  onPressed: () => _adjustRest(15),
                   child: const Text('+15 s'),
                 ),
               ),
@@ -267,6 +265,8 @@ final class _WorkoutExecutionScreenState extends State<WorkoutExecutionScreen> {
   Future<void> _resume() async {
     _session = await widget.activeUseCases.resume(_session.metadata.id);
     if (!mounted) return;
+    final restoredRest = await _restoreActiveRest();
+    if (!mounted || restoredRest) return;
     setState(() => _mode = WorkoutExecutionMode.active);
   }
 
@@ -302,6 +302,10 @@ final class _WorkoutExecutionScreenState extends State<WorkoutExecutionScreen> {
 
   Future<void> _finishSet({required bool skipped}) async {
     final score = double.tryParse(_scoreController.text.trim());
+    final actualTimeMs = DateTime.now()
+        .toUtc()
+        .difference(_seriesStartedAt)
+        .inMilliseconds;
     await widget.activeUseCases.recordCurrentSetResult(
       sessionId: _session.metadata.id,
       programSnapshotId: _plan.programAt(_position).id,
@@ -312,7 +316,9 @@ final class _WorkoutExecutionScreenState extends State<WorkoutExecutionScreen> {
       actualReps: skipped ? null : (_exercise.repsEnabled ? _reps : null),
       actualScore: skipped ? null : (_exercise.scoreEnabled ? score : null),
       scoreUnitSnapshot: _exercise.scoreUnit,
-      actualTimeMs: skipped ? null : (_exercise.timeEnabled ? 0 : null),
+      actualTimeMs: skipped
+          ? null
+          : (_exercise.timeEnabled ? actualTimeMs : null),
     );
 
     final next = _plan.nextPosition(_position);
@@ -322,7 +328,7 @@ final class _WorkoutExecutionScreenState extends State<WorkoutExecutionScreen> {
     }
     final shouldRest = _plan.shouldShowRestAfter(_position);
     if (shouldRest) {
-      await widget.activeUseCases.startRestAfterSet(
+      final rest = await widget.activeUseCases.startRestAfterSet(
         sessionId: _session.metadata.id,
         afterProgramIndex: _position.programIndex,
         afterExerciseIndex: _position.exerciseIndex,
@@ -330,6 +336,7 @@ final class _WorkoutExecutionScreenState extends State<WorkoutExecutionScreen> {
         plannedRestSeconds: _exercise.restSeconds,
       );
       if (!mounted) return;
+      _activeRestStateId = rest.metadata.id;
       _remainingRestSeconds = _exercise.restSeconds;
       _startRestTicker(next);
       setState(() => _mode = WorkoutExecutionMode.rest);
@@ -344,16 +351,73 @@ final class _WorkoutExecutionScreenState extends State<WorkoutExecutionScreen> {
       if (!mounted) return;
       if (_remainingRestSeconds <= 1) {
         timer.cancel();
-        unawaited(_moveTo(next));
+        unawaited(_finishRestAndMove(next));
       } else {
         setState(() => _remainingRestSeconds -= 1);
       }
     });
   }
 
+  Future<bool> _restoreActiveRest() async {
+    final rest = await widget.activeUseCases.findActiveRest(
+      sessionId: _session.metadata.id,
+    );
+    if (!mounted || rest == null) {
+      return false;
+    }
+    final after = ExecutionPosition(
+      programIndex: rest.afterProgramIndex,
+      exerciseIndex: rest.afterExerciseIndex,
+      setIndex: rest.afterSetIndex,
+    );
+    final next = _plan.nextPosition(after);
+    final remaining = _remainingSecondsFor(rest);
+    _activeRestStateId = rest.metadata.id;
+    if (next == null || remaining <= 0) {
+      await _finishRestAndMove(next);
+      return true;
+    }
+    _remainingRestSeconds = remaining;
+    _startRestTicker(next);
+    if (!mounted) return true;
+    setState(() => _mode = WorkoutExecutionMode.rest);
+    return true;
+  }
+
+  int _remainingSecondsFor(ActiveRestState rest) {
+    final elapsedSeconds = DateTime.now()
+        .toUtc()
+        .difference(rest.startedAt.toUtc())
+        .inSeconds;
+    return (rest.adjustedRestSeconds - elapsedSeconds).clamp(0, 9999).toInt();
+  }
+
+  Future<void> _adjustRest(int deltaSeconds) async {
+    final restStateId = _activeRestStateId;
+    setState(() {
+      _remainingRestSeconds = (_remainingRestSeconds + deltaSeconds)
+          .clamp(0, 9999)
+          .toInt();
+    });
+    if (restStateId == null) return;
+    await widget.activeUseCases.adjustRestSeconds(
+      restStateId: restStateId,
+      deltaSeconds: deltaSeconds,
+    );
+  }
+
   Future<void> _skipRest() async {
     _restTicker?.cancel();
     final next = _plan.nextPosition(_position);
+    await _finishRestAndMove(next);
+  }
+
+  Future<void> _finishRestAndMove(ExecutionPosition? next) async {
+    final restStateId = _activeRestStateId;
+    _activeRestStateId = null;
+    if (restStateId != null) {
+      await widget.activeUseCases.skipRest(restStateId: restStateId);
+    }
     if (next == null) {
       await _complete();
       return;
@@ -364,6 +428,8 @@ final class _WorkoutExecutionScreenState extends State<WorkoutExecutionScreen> {
   Future<void> _moveTo(ExecutionPosition position) async {
     _scoreController.clear();
     _reps = 0;
+    _activeRestStateId = null;
+    _seriesStartedAt = DateTime.now().toUtc();
     _session = await widget.activeUseCases.updateProgress(
       sessionId: _session.metadata.id,
       programIndex: position.programIndex,