add support for disabling selection of certain cells / columns

[mymoto23]

Hi @nick-keller,

Great work on the package!

I was wondering if there was an option to disable each cell / columns "active" state - basically disabling selection.

I've gone through the docs but I could only find the "disable" option for each column, which prevents input, but not selection.

I've managed to come up with a hacky workaround where I manually set the selection within the onSelectionChange prop with the ref attached to the Grid component, as such:

	const ref = useRef<DataSheetGridRef>(null);

	return <DataSheetGrid {...props} onSelectionChange={({selection}) => {
		// disable selection over 3rd column
		if (selection.max.col >= 2) {
			ref.current.setSelection(...);
		}
	}} />

It works great, but on some keyboard actions such as "select whole row" or "select next column cell", the selection is affected very briefly, and results in a somewhat buggy animation.

Do you have any plans on adding an option on disabling columns / cells entirely?

Thanks.

[mymoto23]

additionally,
the hack cannot "completely disable" the cell,
as selecting the "completely disabled" cell results in a selection of a nearby cell which is not "completely disabled".