Add intensity percentage selector with repetition hints

src/TrainingPlanner.Application/PlannerOptions.cs

@@ -4,6 +4,7 @@ public class PlannerOptions
 {
     public string DefaultWorkoutName { get; set; } = string.Empty;
     public string DefaultWorkoutDuration { get; set; } = string.Empty;
+    public List<IntensityPreset> IntensityPresets { get; set; } = [];
     public decimal DefaultIntensityPercent { get; set; }
     public int DefaultWeekCount { get; set; }
     public int DefaultSetsCount { get; set; }