feat(db): add maintenance_policy migration 000025

Добавлены таблицы maintenance_policy и maintenance_policy_config_audit для postgres и sqlite; в postgres_maintenance_audit — колонка policy_id.

Co-authored-by: Cursor <cursoragent@cursor.com>

migrations/sqlite/000025_maintenance_policies.down.sql

@@ -0,0 +1,5 @@
+ALTER TABLE postgres_maintenance_audit DROP COLUMN policy_id;
+
+DROP TABLE IF EXISTS maintenance_policy_config_audit;
+
+DROP TABLE IF EXISTS maintenance_policy;