CaMKII Switch — Energy Landscape (2D)

This is the 2D diagrammatic counterpart to the 3D CaMKII holoenzyme simulator: rather than rendering the twelve-subunit kinase in 3D space, it draws the actual mathematical object that determines whether the synapse potentiates or depresses — a one-dimensional potential energy landscape over the phospho-CaMKII fraction P, computed live as the exact antiderivative of the switch's own rate equation. Deliver Ca²⁺ pulse trains and watch a ball roll across that landscape as it reshapes from a single OFF-favoring well into a double well and back, while a live Ca²⁺(t)/P(t) strip chart and a Ca–P phase portrait show the same trajectory from two more angles. Numerical root-finding on the underlying ODE confirmed a genuine bug in the original 3D model's persistence claim, which this version fixes with an explicit CaM-trapping term so the ON state actually survives after Ca²⁺ returns to baseline, matching the real biology and the stated LTP/LTD behaviour.