/**
 * What the plugin knows of its pane when `/diff` runs: whether it opened
 * it and never closed it, whether it drew when a redraw was asked, and the
 * terminal's width as last drawn (null before any draw).
 */
export type PaneBelief = {
  isBelievedOpen: boolean
  wasDrawnWhenProbed: boolean
  columns: number | null
}