Brummel
581c86b091
One iteration, three tasks: (1) extract blueprint_axis_probe and subsume the two existing inline copies of the wrapped-namespace probe (blueprint_sweep_family + blueprint_mc_family) into it — the single source the spec's rationale requires; (2) the --list-axes surface (SweepBlueprintArgs field, valueless-flag parse + standalone guard, list_blueprint_axes, dispatch short-circuit); (3) four E2Es (open lists prefixed names, closed empty, combined-flags reject, malformed-blueprint safety — no panic). refs #169