createColumn
fun <TData, TValue> createColumn(table: Table<TData>, columnDef: ColumnDef<TData, TValue>, depth: Int, parent: Column<TData, TValue>?): Column<TData, TValue>
Constructs a Column from columnDef. Resolves the def against the table's default column def (per-field merge — only non-null fields on columnDef override the defaults), derives an id from id/accessorKey/string header, builds an accessor function for accessor-key/-fn columns, installs the memoised getFlatColumns and getLeafColumns, and runs every registered feature's createColumn hook.
Throws IllegalStateException when no id can be derived.