Revert "A streaming reply's words come into focus as they arrive, fading in from a 4px blur as Streamdown's blurIn does, rather than only fading. The theme gains --animate-blur-in, its blur-in keyframes, and a --blur-in token for how blurred a word starts, since the app doesn't load Streamdown's stylesheet. Timing, the cascade, list markers, and reduced motion are as before."