Command data should be typed as JSON serializable

[alloy]

Currently the doc indicates this should be serialisable, but the typing is not constrained in any way. We should consider adding a typing like this one:

type Json =
    | string
    | number
    | boolean
    | null
    | Json[]
    | { [key: string]: Json }
    ;

export interface NovaCommand<TData extends Json> {
  // ...
}

[alloy]

Kerryn Frampton (@kerrynf) Just for my understanding, could you expand on the requirement for it to be serializable?