You could space tiki torches or something similar around the pool, and run a mesh fence like this between them: https://www.lowes.com/pd/GARDEN-CRAFT-50-ft-x-2-ft-Green-PVC-Coated-Steel-Welded-Wire-Rolled-Fencing-with-Mesh-Size-2-in-x-3-in/1000367323
Easy to take down and roll up, and you don’t have to worry about removing posts, you just light them to provide some light for the guests!
I suppose another option could be to attach a retractable lead outside the door. If you could set the length so she could reach the grass but not the pool, you could just clip her onto it when she is outside