Let players indicate when they're done with PREPARATION phase

[devguy22]

It can be useful to the dealer to know when each player has completed filling out their thoughts. This will help them to know when to switch to TURN phase without bugging the players over and over again.

This could be a 'ready' indicator light next to their name on a roster only seen by dealer. Maybe a player can press an "I'm ready" button on their screen to indicate (toggleable).