fix(test): adapt health check assertion to Phase 4 status value change

tests/integration/test_server_e2e.py

@@ -209,7 +209,7 @@ class TestFullFlow:
         response = client.get("/api/v1/health")
         assert response.status_code == 200
         data = response.json()
-        assert data["status"] == "ok"
+        assert data["status"] in ("ok", "healthy")
 
     def test_llm_usage_after_tasks(self, client):
         """LLM usage stats available after task execution"""