v2.5更新

backend/models/subject.py

@@ -76,6 +76,12 @@ class SubjectModel:
     
     @staticmethod
     async def delete(subject_id: int) -> bool:
+        """软删除科目（设置 is_active = 0），如果已禁用也返回成功"""
+        subject = await SubjectModel.get_by_id(subject_id)
+        if not subject:
+            return False
+        if subject.get("is_active") == 0:
+            return True  # 已禁用，视为成功
         sql = "UPDATE subjects SET is_active = 0 WHERE subject_id = %s"
         result = await execute_update(sql, (subject_id,))
         return result > 0