Add question bank mastery paths and gap questions

api/QuestionsApi/Models/DashboardModels.cs

@@ -49,6 +49,32 @@ public sealed class DashboardSystemPerformance
     public int Correct { get; set; }
     public int Total { get; set; }
     public int Accuracy { get; set; }
+    public int MasteryScore { get; set; }
+    public string MasteryState { get; set; } = MasteryStates.Unseen;
+    public int DistinctQuestions { get; set; }
+    public int Difficulty4PlusSuccessful { get; set; }
+    public int PendingReviews { get; set; }
+    public DateTime? LastEvidenceUtc { get; set; }
+    public bool RefreshDue { get; set; }
+    public DashboardMasteryAction RecommendedAction { get; set; } = new();
+}
+
+public static class MasteryStates
+{
+    public const string Unseen = "unseen";
+    public const string Learning = "learning";
+    public const string Practicing = "practicing";
+    public const string Strong = "strong";
+    public const string Mastered = "mastered";
+}
+
+public sealed class DashboardMasteryAction
+{
+    public string Type { get; set; } = "practice";
+    public string Label { get; set; } = "Start learning";
+    public int QuestionCount { get; set; } = 10;
+    public int? DifficultyMin { get; set; }
+    public int? DifficultyMax { get; set; }
 }
 
 public sealed class DashboardActivityDay

api/QuestionsApi/Models/Question.cs

@@ -23,6 +23,7 @@ public class Question
     public Dictionary<string, int> ChoiceSelectionPercentages { get; set; } = [];
     public string Discipline { get; set; } = "";
     public string System { get; set; } = "";
+    public string Step3System { get; set; } = "";
     public string PerformanceCategory { get; set; } = "";
     public int Difficulty { get; set; } = 1;
     public List<QuestionLab> Labs { get; set; } = [];

api/QuestionsApi/Models/QuestionRequests.cs

@@ -3,6 +3,7 @@ namespace QuestionsApi.Models;
 public class QuestionSearchRequest
 {
     public string? System { get; set; }
+    public string? Step3System { get; set; }
     public string? Discipline { get; set; }
     public List<string> Tags { get; set; } = [];
     public int? DifficultyMin { get; set; }

api/QuestionsApi/Models/QuestionResponse.cs

@@ -1,3 +1,5 @@
+using QuestionsApi.Services;
+
 namespace QuestionsApi.Models;
 
 public class QuestionResponse
@@ -18,6 +20,7 @@ public class QuestionResponse
     public string ChoiceSelectionRateBasis { get; set; } = "presented";
     public string Discipline { get; set; } = "";
     public string System { get; set; } = "";
+    public string Step3System { get; set; } = "";
     public string PerformanceCategory { get; set; } = "";
     public int Difficulty { get; set; }
     public int QuestionElo { get; set; } = 1000;
@@ -59,6 +62,7 @@ public class QuestionResponse
                 .ToDictionary(),
             Discipline = question.Discipline,
             System = question.System,
+            Step3System = Step3SystemCatalog.Normalize(question) ?? "",
             PerformanceCategory = RatingCategory.Normalize(question.PerformanceCategory, question.System, question.Discipline),
             Difficulty = question.Difficulty,
             QuestionElo = questionElo,

api/QuestionsApi/Models/ReviewQueueModels.cs

@@ -55,6 +55,7 @@ public sealed class ReviewQueueNextRequest
 {
     public List<string> ExcludeExternalIds { get; set; } = [];
     public bool SupportsChoicePools { get; set; } = true;
+    public string? Step3System { get; set; }
 }
 
 public sealed class ReviewQueueNextResponse