Refresh Hosted Models

Ask the provider again and offer whatever is newly listed.

Nothing already offered is removed, even when the provider no longer lists it. New models follow the offer rule, seeded with the community default price and off when nothing prices them. A seeded price nobody changed moves with the default. An offered model whose stored price has since been deleted is seeded again, or switched off where the default does not price it, even one an operator switched on: a refresh never switches a model on.