There are plenty of topics here where I’ve said that to me, selling add-ons is tacky so I won’t go into that again.
But if you want to, there’s no reason why you can’t have a
menu, a price list, in your rental showing what you sell and the prices. Make it attractive and say on the list why you are sharing these local items with your guests if they should wish.
You or your co-host can point the list out during the house tour and this will make it feel less like a commercial venture and more that you want to share the bounties of the locality with guests if they wish.
Depending on the length of stay, I’d leave a little produce in the rental as a freebie, point it out to the guest during the house tour and say ‘oh, and if you’d like more eggs/produce from our garden, there’s a list over there showing what we have and the prices…’
Don’t worry about that. Airbnb has done its job by introducing the guest to you and processing the payment. Add-ons and repeat stays are now yours.
By the way, I wouldn’t charge for weekly cleaning. It’s nice for the guest but it’s more for your benefit so that you’re keeping an eye on things on a regular basis and making sure that the rental is in good shape.