feat(t208): close candidate decision feedback loop

backend-api/internal/repository/sqlite/execution_result_repository.go

@@ -183,6 +183,15 @@ func (s *Store) StoreExecutionCandidates(
 	if err != nil {
 		return false, repositoryFailure(err)
 	}
+	if err := storeCandidateDecisionDataset(
+		ctx,
+		tx,
+		write,
+		candidate,
+		expired,
+	); err != nil {
+		return false, err
+	}
 	if err := insertExecutionResultRequest(ctx, tx, write, nil); err != nil {
 		return false, err
 	}
@@ -825,6 +834,15 @@ func getExecutionReport(
 	} else if !errors.Is(err, sql.ErrNoRows) {
 		return nil, repositoryFailure(err)
 	}
+	report.DecisionDataset, err = getCandidateDecisionDataset(
+		ctx,
+		queryer,
+		taskID,
+		executionID,
+	)
+	if err != nil {
+		return nil, err
+	}
 	var outcome domain.ExecutionOutcome
 	var mode, hash, result, reason, selected, evidenceIDs, code, message, step sql.NullString
 	var retryable sql.NullBool