bugfix

migrations/0018_phase_gates.down.sql

@@ -0,0 +1,10 @@
+-- 回滚 0018：丢弃指针表与 verdict 列，恢复三阶段 CHECK。
+-- implementing/reviewing 产物在回滚时若存在会违反旧 CHECK，先删除它们（旧 schema 无处安放）。
+DROP TABLE IF EXISTS requirement_phase_pointers;
+
+ALTER TABLE requirement_artifacts DROP COLUMN IF EXISTS verdict;
+
+DELETE FROM requirement_artifacts WHERE phase IN ('implementing','reviewing');
+ALTER TABLE requirement_artifacts DROP CONSTRAINT requirement_artifacts_phase_check;
+ALTER TABLE requirement_artifacts ADD CONSTRAINT requirement_artifacts_phase_check
+  CHECK (phase IN ('planning','prototyping','auditing'));