cli: make auth status/logout context-only (COR-393)

resolveStatusTarget loses its legacy-keyring fallback and probes only the active context. With no login at all, auth status prints an informational "Not logged in. Run 'entire login'." (exit 0) and logout no-ops — neither ever targeted a default host with a stale identity. logout's revoke now takes the already-resolved bearer instead of re-reading a legacy store slot, and the legacy-slot cleanup in --all-contexts goes with it.