Iteration 2 of cycle D: SweepPoint carries a full RunReport (closure bound ->
RunReport), all engine + CLI callers rethreaded in lockstep so the workspace
returns green; the hand-rolled sweep_point_to_json retired (each point prints
via RunReport::to_json); new aura-registry crate (open/append/load/rank_by +
RegistryError), built and unit-tested but not yet CLI-wired. The aura sweep
goldens pin the per-point manifest params, not the volatile git-HEAD commit.
refs #33
