fix: 修复重复岗位/团队导致的同步失败问题

backend/app/services/employee_sync_service.py

@@ -153,11 +153,11 @@ class EmployeeSyncService:
         
         department_name = department_name.strip()
         
-        # 检查团队是否已存在
+        # 检查团队是否已存在（使用limit(1)避免重复数据报错）
         stmt = select(Team).where(
             Team.name == department_name,
             Team.is_deleted == False
-        )
+        ).limit(1)
         result = await self.db.execute(stmt)
         team = result.scalar_one_or_none()
         
@@ -202,11 +202,11 @@ class EmployeeSyncService:
         
         position_name = position_name.strip()
         
-        # 检查岗位是否已存在
+        # 检查岗位是否已存在（使用first()避免重复数据报错）
         stmt = select(Position).where(
             Position.name == position_name,
             Position.is_deleted == False
-        )
+        ).limit(1)
         result = await self.db.execute(stmt)
         position = result.scalar_one_or_none()