Thanks for reporting. I changed the notification logic to say "0" if you don't have any stars.
This one is a little tricky though. Ordered showroom items expire after 30 days. If stars are moved off a bot with pending orders, the order does not get deleted, but it cannot be seen in the showroom (just the sidebar notification before my change) or bought unless you have at least 1 star. So in one sense, saying "1" is actionable - if your bot gets a star back, you can buy the order(s). In another sense though, that's kind of a high bar for the notification being actionable and not in the spirit of what the notifications are supposed to mean - that's why I made the change I made.
Maybe a "best of both worlds" solution would be to show pending orders to bots without stars on the showroom page, but don't allow the bot to actually buy them. That way you still have a way to finding out whether there are pending orders or not. Then again, maybe this is a fair change since it's sort of a loophole that you can determine whether a bot with no stars has pending orders waiting. The loophole still exists - players will just have to be more organized in tracking the orders manually now that the game won't tell you when you have no stars.
Another direction I could have gone is to delete pending orders if a bot loses all of its stars. Or even tougher enforcement would be to delete pending orders for which the new number of stars would no longer be able to order, e.g. 10 stars -> 9 stars = 1 day orders deleted. I don't think this is necessary though.