Changelog
- Handle 2171 action 4 from the seat prompt's Watch button: PokerManager.Watch opens the room with a 2090 audience join (join type 2) so the spectator shows in the watchers list
- Send every table packet to spectators through PokerTable.Viewers; per-viewer deals hide every hole card from them
- Rebuild a hand in progress for a new spectator with MsgShowHandLostInfo (2098), Texas and ShowHand layouts
- Leave, teleport and logout remove a spectator with 2096; a spectator may take a seat at the table they watch
- Correct the 2171 action names: 2 offline and 3 sit waiting are server-only, 4 is watch