Hehe, because cats are tricky little rascals! Believe me dogs are worse with their digging of holes!
By the way your veggie garden is so pretty! I start to consider lifted bedding or container gardening, I'm not sure how you call it on english, sorry! Because here we just put it at ground and is much easy for pet's digging and difficult for weeding.
O yes, our dog also digs large holes. I hate it when he does that!!
I've started to sow my veggies in that grey bin, which is actually the bottom of the cage we used for our guinea pigs. Now the seeds start to grow I have to move them so they have more room. My son made me two vegetable garden containers from wood. You can buy them complete, but then they are really expensive. It's much easier to make them yourself.
This is one my son made for me.
The photo's below are to show you what you can do with them
This is the first year I do this. I plan to add a bit each year. Not only with veggies, but also with flowers. I think it looks so beautiful. And you can make them in any shape you want, you can also make them high, by adding wooden legs under them.