khan: wip scries, moves, request ids
khan: wip scries, moves, request ids

Also clean up some types and remove obsolete TODOs.

urbit/urbit,urbit/urbit,urbit/urbit,ngzax/urbit,ngzax/urbit,ngzax/urbit,ngzax/urbit,ngzax/urbit,ngzax/urbit,urbit/urbit,urbit/urbit,urbit/urbit,ngzax/urbit,urbit/urbit