test(core): update HRM test case to correct structure

tests/test_model_support.py

@@ -39,12 +39,12 @@ def test_model_support_rejects_non_eager_attention() -> None:
 def test_model_support_accepts_hrm_layout() -> None:
     layer = SimpleNamespace(attention=object())
     model = SimpleNamespace(
-        model=SimpleNamespace(h_stack=SimpleNamespace(layers=[layer, layer])),
+        model=SimpleNamespace(h_stack=[layer, layer]),
         config=SimpleNamespace(_attn_implementation="eager"),
     )
 
     support = describe_model_support(model)
 
     assert support.supports_attribution is True
-    assert support.layer_path == "model.h_stack.layers"
+    assert support.layer_path == "model.h_stack"
     assert support.attention_attr == "attention"