type 0 turns out not to need a UDP transport. MessageManager::sendUdpMessage
checks for a socket and a valid connection, and falls straight back to
sendMessage when there is neither - we never send UdpConnectionInfoMessage,
so the client has no socket and the sector traffic arrives on the tcp
connection we already have.
so SectorCommandMessage, 12904, is decoded now: a client tick, a client
checksum and an optional command. a card played this way goes through the
same summon path as before. the client stops sending EndClientTurnMessage
in a battle - sendEndTurn asserts on isImmediateMessageExecution - so the
checksum comparison moves onto the sector command, which carries the same
two numbers.
with the type at 0 the client no longer simulates. it renders what the
snapshot says, which is why the snapshots start flowing again: the gate
on them was the battle type all along. the bot's cards reach the player
for the first time, because there is finally one simulation rather than
two arguing.