So I started a quest that involved the spy and one of the priests and right as the quest started, the spy had been crafting something and the game went and tried to cancel it. The task has a red X over it, but it's not going away. Since then, she's been stuck in the same animation for days.

I tried canceling the quest and even moving the table or her with cheats, and nothing stopped her. I even tried just letting her starve to death, but that just adds the nonremovable death task and then nothing else happens.

Any idea how I can stop this? I'm even fine killing her off somehow if it means I can do something with a spy again.

This has worked for me 5 times when sims get stuck.

Go to buy mode and simply do a lot of stuff on/around the sim.
Buy stuff sell stuff move stuff.

One time all I had to do was place a Cask in the square next to the sim and it was Ok.

If that doesnt work then look for the Mods thread and install Ricks debug from p1. It has a reset in it.