Zilla had a seizure and died last night.
In the end, her kidney function never recovered, but at least we were able to ensure that her last weeks were warm, comfortable and well-nourished.
And although it's not as important as her comfort, she seemed to genuinely appreciate us, too. Although she disdained being picked up as she grew stronger, she sought out our company, sitting as a companionable loaf by the fire, and developed the habit of climbing onto our feet and refusing to move. (Her feet now.)
She was a sweet little cat and she deserved better than to die on the pavement in the rain. I'm glad we were able to give her that much, at least.
Sleep well, little kitty.