회기 연속성과 멀티 케이스 계약을 영속화

apps/api/app/routes/teacher.py

@@ -16,6 +16,8 @@ from ..session_read_model import (
     learner_visible_turns,
     missing_session_evaluation_record,
     stage_label,
+    teacher_evaluation_failure,
+    teacher_evaluation_failure_message,
 )
 from ..services import session_metrics
 from ..stage_contract import STAGE_LABEL_VALUES
@@ -298,6 +300,7 @@ def _summary(
     learner_turns = sum(1 for turn in visible_turns if turn.speaker == "counselor")
     client_turns = sum(1 for turn in visible_turns if turn.speaker == "client")
     evaluation_status = _evaluation_status_value(summary_evaluation_record)
+    evaluation_failure = teacher_evaluation_failure(summary_evaluation_record)
     return TeacherSessionSummary(
         session_id=sess.session_id,
         learner_id=sess.learner_id,
@@ -322,9 +325,7 @@ def _summary(
             summary_evaluation_record,
             has_visible_turns=bool(visible_turns),
         ),
-        evaluation_error=(
-            str(summary_evaluation_record.get("error") or "") if summary_evaluation_record else None
-        ),
+        evaluation_error=teacher_evaluation_failure_message(evaluation_failure),
     )