#42 registries: label/milestone list sorted by name (render-time)

SOURCE: swarm friction #8 (verified: labels.md/milestones.md list in insertion order; a closed test milestone renders above real ones). FIX: f0rge label list and f0rge milestone list render sorted by name (stable, render-time only — never stored state). Update any golden/needle tests that pinned insertion order. DONE: both registries list sorted; no schema change.