精简后端功能模块并补充教学互动

app/repositories/teaching_repository.py

@@ -0,0 +1,25 @@
+from sqlalchemy import select
+from sqlalchemy.orm import Session, selectinload
+
+from app.models.source_case import CaseBase
+
+
+class TeachingRepository:
+    """教学互动仓储：读取 case_base + teaching_case 以及评分相关扩展数据。"""
+
+    def __init__(self, db: Session) -> None:
+        self.db = db
+
+    def get_active_teaching_case(self, case_id: int) -> CaseBase | None:
+        """教学病例读取：校验病例已发布、已启用且存在 teaching_case 扩展。"""
+        stmt = (
+            select(CaseBase)
+            .options(
+                selectinload(CaseBase.teaching_case),
+                selectinload(CaseBase.traditional_case),
+                selectinload(CaseBase.scoring_rules),
+            )
+            .where(CaseBase.id == case_id, CaseBase.status == 1, CaseBase.publish_status == 1)
+        )
+        case = self.db.scalar(stmt)
+        return case if case and case.teaching_case else None