Exclude sample exam simulations from the dashboard's readiness score

The SUPER-role "preview results" QA tooling seeds a completed
ExamSimulation with scripted (not real) answers, flagged IsSample.
The dashboard's readiness lookup picked whichever completed
simulation was most recent regardless of that flag, so running the
QA preview on an account could override its real Exam Readiness card
with a synthetic pass probability. Recent-activity/weekly-activity
queries got the same exclusion since they read from the same
collection for the same reason.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

api/QuestionsApi.Tests/DashboardTests.cs

@@ -199,4 +199,35 @@ public sealed class DashboardTests
     {
         Assert.Equal(expected, DashboardStore.ReadinessLabel(passProbability));
     }
+
+    [Fact]
+    public void SelectLatestReadinessScoreSkipsSampleSimulationsEvenWhenMostRecent()
+    {
+        var today = new DateTime(2026, 7, 25, 0, 0, 0, DateTimeKind.Utc);
+        var simulations = new[]
+        {
+            CompletedSimulation(isSample: true, completedUtc: today, passProbability: 0.98),
+            CompletedSimulation(isSample: false, completedUtc: today.AddDays(-3), passProbability: 0.12)
+        };
+
+        var score = DashboardStore.SelectLatestReadinessScore(simulations);
+
+        Assert.NotNull(score);
+        Assert.Equal(0.12, score.PassProbability);
+    }
+
+    [Fact]
+    public void SelectLatestReadinessScoreReturnsNullWhenOnlySamplesExist()
+    {
+        var simulations = new[] { CompletedSimulation(isSample: true, completedUtc: DateTime.UtcNow, passProbability: 0.98) };
+
+        Assert.Null(DashboardStore.SelectLatestReadinessScore(simulations));
+    }
+
+    private static ExamSimulation CompletedSimulation(bool isSample, DateTime completedUtc, double passProbability) => new()
+    {
+        IsSample = isSample,
+        CompletedUtc = completedUtc,
+        Score = new ExamSimulationScore { PassProbability = passProbability }
+    };
 }

api/QuestionsApi/Services/DashboardStore.cs

@@ -79,10 +79,10 @@ public sealed class DashboardStore
         var ccsAllAttemptsTask = _ccsAttempts.Find(value => value.UserId == userId).ToListAsync();
         var completedCcsCountTask = _ccsAttempts.CountDocumentsAsync(value => value.UserId == userId
             && value.State == CcsAttemptStates.Completed && value.CompletedUtc.HasValue);
-        var simulationsTask = _simulations.Find(value => value.UserId == userId && value.CreatedUtc >= trendStart).ToListAsync();
+        var simulationsTask = _simulations.Find(value => value.UserId == userId && !value.IsSample && value.CreatedUtc >= trendStart).ToListAsync();
-        var latestScoreTask = _simulations.Find(value => value.UserId == userId
+        var completedSimulationsTask = _simulations.Find(value => value.UserId == userId
             && value.State == ExamSimulationStates.Completed && value.Score != null)
-            .SortByDescending(value => value.CompletedUtc).FirstOrDefaultAsync();
+            .SortByDescending(value => value.CompletedUtc).ToListAsync();
         var bookmarkCountTask = _bookmarks.CountDocumentsAsync(value => value.UserId == userId);
         var notepadTask = _notes.Find(value => value.UserId == userId).FirstOrDefaultAsync();
         var reviewAttemptsTask = _reviewQueue.GetReviewsSinceAsync(userId, weekStart);
@@ -90,7 +90,7 @@ public sealed class DashboardStore
         var flashcardReviewsTask = _flashcardSchedules.GetReviewsSinceAsync(userId, weekStart);
         var dynamicReviewsTask = _dynamicQuestions.DueReviewsAsync(userId, nowUtc);
         await Task.WhenAll(attemptsTask, ratingTask, ccsRatingTask, ccsAttemptsTask, ccsAllAttemptsTask, completedCcsCountTask,
-            simulationsTask, latestScoreTask, bookmarkCountTask, notepadTask, reviewAttemptsTask, flashcardCountsTask,
+            simulationsTask, completedSimulationsTask, bookmarkCountTask, notepadTask, reviewAttemptsTask, flashcardCountsTask,
             flashcardReviewsTask, dynamicReviewsTask);
 
         var attempts = attemptsTask.Result;
@@ -112,7 +112,7 @@ public sealed class DashboardStore
         var ccsTotalTask = _ccsRatings.CountDocumentsAsync(FilterDefinition<CcsUserRating>.Empty);
         await Task.WhenAll(qbankHigherTask, qbankTotalTask, ccsHigherTask, ccsTotalTask);
 
-        var latestScore = latestScoreTask.Result?.Score;
+        var latestScore = SelectLatestReadinessScore(completedSimulationsTask.Result);
         var accuracySampleSize = recentAnswered.Count;
         var firstAttemptAccuracy = Percentage(recentAnswered.Count(value => value.IsCorrect), recentAnswered.Count);
         var performanceTrend = BuildPerformanceTrend(attempts, ratingTask.Result, ccsAllAttemptsTask.Result, ccsRatingTask.Result, today);
@@ -190,6 +190,13 @@ public sealed class DashboardStore
     public static string ReadinessLabel(double passProbability) =>
         passProbability >= 0.7 ? "High" : passProbability >= 0.4 ? "Medium" : "Low";
 
+    // completedSimulationsByRecency must already be sorted newest-first (by CompletedUtc).
+    // Sample simulations (QA-only, seeded via the SUPER-role "preview results" tooling with
+    // scripted answers) never reflect real performance, so they're skipped here rather than
+    // in the Mongo filter - keeping the "which one counts" decision unit-testable.
+    public static ExamSimulationScore? SelectLatestReadinessScore(IEnumerable<ExamSimulation> completedSimulationsByRecency) =>
+        completedSimulationsByRecency.FirstOrDefault(value => !value.IsSample)?.Score;
+
     public static int CalculateCurrentStreak(IEnumerable<DateTime> activeDates, DateTime todayUtc)
     {
         var dates = activeDates.Select(value => value.Date).ToHashSet();