修复工作流表删除迁移幂等

backend/tests/test_migration_safety.py

@@ -8,6 +8,15 @@ def test_is_locked_migration_is_idempotent():
     assert 'if "is_locked" in columns:' in source
 
 
+def test_removed_workflow_tables_are_dropped_conditionally():
+    source = Path("alembic/versions/20260116_05_remove_document_workflows.py").read_text(encoding="utf-8")
+
+    assert 'if "workflow_actions" in tables:' in source
+    assert 'if "version_workflows" in tables:' in source
+    assert 'if "workflow_nodes" in tables:' in source
+    assert 'if "workflow_templates" in tables:' in source
+
+
 def test_migration_state_check_script_exists():
     source = Path("scripts/check_migration_state.py").read_text(encoding="utf-8")