Downgrade impact

What a downgrade takes away, said before it happens. The new price and the day, then only what goes over the new plan's limits, worst first, each with what happens to it and, where it helps, a way to decide now (who keeps a seat). What is kept is said too. Scheduling the move asks twice when something will be lost, and once scheduled it can be undone until the day. Counts AI SDK token usage against the new plan's allowance; Plan picker sends a downgrade here.