feat: add portfolio graph enrichment

tests/unit/service/test_dependency_degradation.py

@@ -24,6 +24,37 @@ async def test_neo4j_rejects_unapproved_relationship() -> None:
         await RelationshipService(FailingGraph()).neighbors(1, "DELETE_ALL")
 
 
+@pytest.mark.asyncio
+async def test_portfolio_graph_context_uses_fixed_query_and_filters_noise() -> None:
+    class Graph:
+        async def execute_query(self, query: str, **parameters: object) -> list[object]:
+            assert "HOLDS" in query and "EXPOSED_TO_INDUSTRY" in query
+            assert parameters == {"customer_id": 7, "limit": 20}
+            return [
+                {"industry_name": "科技", "product_count": 2},
+                {"industry_name": "单产品行业", "product_count": 1},
+            ]
+
+    result = await RelationshipService(Graph()).portfolio_industry_context(7)
+    assert result == {
+        "degraded": False,
+        "overlaps": [
+            {"industry_name": "科技", "product_count": 2},
+            {"industry_name": "单产品行业", "product_count": 1},
+        ],
+    }
+
+
+@pytest.mark.asyncio
+async def test_portfolio_graph_context_failure_is_degraded() -> None:
+    from app.service.portfolio_analysis_service import PortfolioAnalysisService
+
+    service = PortfolioAnalysisService(graph_service=RelationshipService(FailingGraph()))
+    result = await service._graph_context(7)
+    assert result["degraded"] is True
+    assert str(result["reason"]).startswith("neo4j_unavailable")
+
+
 @pytest.mark.asyncio
 async def test_model_router_excludes_unhealthy_endpoint() -> None:
     from app.model.configuration import ModelEndpointConfig