ConstReadonlyDarkGrid: "enableDarkGrid"Whether the grid renders dark when the app is dark (Excel-style: dark app, optional dark grid).
ReadonlyDarkImages: "enableDarkImages"Whether images invert in a dark grid.
ReadonlyMode: "themeMode"The user's light/dark override (null = follow system).
Owned via usePersistentState against the surrounding PersistentStateProvider (Studio, or a
standalone host). A consumer that wants to read or set them (e.g. a VS Code host driving the mode from
its editor theme) does so with the same key, or by supplying its own provider/store. They are
intentionally not component props — appearance is state, theme customization is config (see
Studio.theme).
A host changes the starting value of any of these with PersistentStateProvider's defaultValues;
the user's own choice still wins.
Persistence keys for the spreadsheet's self-managed appearance state.