fix: route None/degraded diagnoses to lapse; abort on high degrade rate

core/evolution/diagnose.py

@@ -1489,12 +1489,15 @@ def _build_skill_case_packs(
             if qm.correct:
                 continue
             attr = attribution_map.get(qm.question_id)
-            if attr is not None and attr.cause_category == "lapse":
-                if attr.lapse_note and attr.lapse_note.strip():
+            # 仅明确 defect 且非 degraded 才进正文进化路径；
+            # lapse / cause_category=None（判别失败）/ degraded（judge 解析失败）一律保守走 lapse，
+            # 不以降级或未判定信号驱动错误进化。
+            is_defect = attr is not None and attr.cause_category == "defect" and not qm.degraded
+            if not is_defect:
+                if attr is not None and attr.lapse_note and attr.lapse_note.strip():
                     lapse_notes.append(attr.lapse_note)
                 continue
-            et = attr.error_type if attr else "mixed"
-            wrong_by_error[et].append(qm)
+            wrong_by_error[attr.error_type].append(qm)
 
         # 单条 fallback
         n_body_failures = sum(len(group) for group in wrong_by_error.values())