test: 修正列渲染断言——SQLAlchemy 会对保留字加反引号

monitor_run.trigger 是 MySQL 保留字，渲染出来是 `trigger`。这比之前手写的列清单更正确：
清单里的裸 trigger 会直接语法错误。断言改为剥掉引号后比对列名。

tests/test_monitor_column_migration.py

@@ -34,7 +34,12 @@ def _ddl(column: Column) -> str:
 def test_column_renders_as_ddl(column):
     ddl = db._column_ddl(column)
 
-    assert ddl.startswith(column.name)
+    # SQLAlchemy back-quotes an identifier only when it has to, so the rendered
+    # name matches the column's with the quoting stripped -- which is the case for
+    # reserved words like monitor_run.trigger. That quoting is a feature: the
+    # hand-kept list this replaced would have emitted bare `trigger` and died on a
+    # syntax error.
+    assert ddl.split(" ", 1)[0].strip("`") == column.name
     # MySQL refuses AUTO_INCREMENT together with the DEFAULT this helper appends
     # to NOT NULL columns.
     assert "AUTO_INCREMENT" not in ddl