Let retainers relist from their inventory

Sellers should have the option for their retainers to automatically make a new listing at the same price and stack size when a stack sells, as long as the retainer has sufficient items in their inventory.

This would let sellers continue to sell the stack size they want, but sellers wouldn't have to micromanage the stacks as much. Buyers would still have an incentive to buy full stacks, because it's annoying to click "Buy" 99 times instead of buying one stack with 99 items in it.

Also, this is useful to sellers who want to sell multiple full stacks of the same item. Instead of using one retainer slot for each full stack, they could use 1 retainer slot that automatically refreshes when it sells.

Players that put a little 'effort' into the game should reap the rewards of stopping by the public bell or inn room frequently to keep their goods up on the market.

Next players will want their retainers to relist items when they get under cut