refactor: share INFRA stop-reason set from core.evolution

tests/unit/test_harness_validate.py

@@ -199,6 +199,15 @@ def _make_all_infra_mock(log: HarnessLog, stop_reason: str):
     return mock_fn, call_log
 
 
+def test_infra_stop_reasons_single_source() -> None:
+    """app 侧 INFRA_STOP_REASONS 复用 core 常量（同一对象），杜绝未来漂移（M-2）。"""
+    from app.harness import validate
+    from core.evolution import diagnose
+
+    assert validate.INFRA_STOP_REASONS is diagnose.INFRA_STOP_REASONS
+    assert frozenset({"error", "parse_error"}) == diagnose.INFRA_STOP_REASONS
+
+
 # ===========================================================================
 # 数据类型测试
 # ===========================================================================