Support Blur my Shell window filter while scrolling

[cloudglides]

In GNOME Shell, window animations are implemented by creating clones of windows during transitions. These clones are animated (e.g., scaled, moved, or faded) while the original windows are temporarily hidden. Once the animation completes, the clones are discarded, and the original windows are shown in their new state.

Effects like blur applied to the original windows are not automatically inherited by the clones. To handle this, paperwm would need to manually apply the effect to the clone during the animation.

[cloudglides]

Screencast.from.2025-01-13.11-31-37.mp4