Currently, a single "Show Animations" checkbox in DevIndex controls both the header canvas animation speed and the grid sparkline animations. This is too coarse.

We need to split this into two granular controls:

1. Slow Header Canvas: Controls the speed of the background canvas in the header. State will live in ViewportStateProvider.
2. Animate Grid Sparklines: Controls the sparkline pulses inside grid cells. State will live in home/MainContainerStateProvider.

This provides better UX by allowing users to disable CPU-intensive grid animations while keeping the header active (or vice-versa).