- Clients now handle the host closing the arena: bank winnings if
still alive (retire), reset the HUD, and return to the camp menu
instead of being stranded in a dead world
- Death in co-op offers Spectate when a teammate is still fighting:
closes the results overlay and watches the run; the escape menu
gains a "Back to Camp" option for dead spectators to leave later
- Late joiners receive the current wave number on connect so their
HUD doesn't sit on "Prepare..." until the next wave starts