Manual (server) filtering

[cristisp]

With the upgrade to V8, we now have this type below that describes an individual column filter shape.

declare type ColumnFilter = {
    id: string;
    value: unknown;
};

Is there a way to extend this? My current filtering setup (using v7) requires additional fields such as {op: string} that I cannot currently use. I tried to extend ColumnFilter's value prop (and access filter value using .value.value) but I can't get around the "unknown" type for value.