37b9a68017
Foundation document for the future test_infra_hardening track that will address session-scoped live_gui fixture isolation, silent __getattr__/__setattr__ contract assumptions, and similar test infrastructure fragility. Also documents the test_rag_phase4_final_verify batch failure that surfaces after the __getattr__ fix unblocks test_full_live_workflow. The RAG test failure is NOT a regression - it reproduces on pre-fix HEAD too. It's a pre-existing test isolation issue (the live_gui fixture is session-scoped, so state from the 4 sims pollutes the controller).