#799 Holk: lowering and lowered sail states

[Sahits GmbH]

ships/holk/holk.blend has pressure-baked cloth sails plus MainSail_for_Animation/BowSail_for_Animation curve-deform rigs, but no rig for the aft sail, and both sail sets render at once. Decide whether the intent is cloth for under way and curve-deform for lowering (Snaikka pattern). Then fix the visibility, add the aft-sail rig, and build the frozen lowered states for health 20–100.