执行 Ruff 安全自动修复

tests/test_migrations.py

@@ -68,8 +68,8 @@ class TestMigrationSmoke:
 
     def test_full_chain_applies_on_fresh_sqlite_and_matches_models(self):
         """空库执行整条迁移链，校验表/列/索引与模型元数据对齐。"""
-        from web.backend.database import Base
         import web.backend.database as database_module
+        from web.backend.database import Base
 
         original_url = database_module.DATABASE_URL
         with tempfile.TemporaryDirectory() as tmp: