Stability checkpoint stable-v1.0.27 (UI) — Phase 4.2 wave continued: 6 Auth0BridgeService tests covering the SDK→AuthService translation lifecycle (login token storage, error absorption keeping outer stream alive, logout clearing, no spurious actions). Cumulative UI Phase 4.2 across v1.0.23-27: 89 new UI tests across 7 specs. Post-merge main pipeline #388 SUCCESS.