fc568ae0fa
Phase 3 Task 7. Regression net pinning the #485 negative on every FetchAndCache seam — nothing rebuilds, nothing is torn down on a failure: (1) a null fetch mid-steady-state (all endpoints down / NotFound / SHA mismatch — indistinguishable to the actor) keeps the served address space and revision (no RebuildAddressSpace for the failed revision); (2) a zero-length blob handed to the actor fails via ReconcileDriversFromBlob's own #485 guard, independent of the fetcher's null contract; (3) a corrupt cache at boot (surfaced as GetCurrentUnkeyedAsync == null) lands Steady-no-revision and applies NOTHING — never a partial address space. No new mechanism; all green as a net. Removing the #485 empty guard reddens the zero-length test. Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW