aef6122c4f
Documents the Tier 1 investigation findings (environmental pollution from live_gui tests leaking temp paths into the session-scoped subprocess via ui_files_base_dir) and the 3 fixes applied. 28/29 RAG tests now pass; the remaining failure (test_rag_phase4_final_verify) is a different issue (rebuild not being triggered) that needs user investigation. Diag writes are not appearing in the subprocess log even though the test sees other behaviors from the same code paths.