Play SfxOpen on floor start, ding each blocked pulse, and close on the countdown into the next floor
- start a randomized chase track per pulse (avoiding immediate repeats) and fade it out via tween on block or doors closing
- Delay the auto-close after the final survivor by 0.25s so the ding doesn't collide with the close sound!
- Move elevator panel logic out of HUD; HUD now listens for signals to update floor, saved, people, and score labels
- Add scaling rescue threshold that grows as you descend, with bonus points for exceeding it
- Add per-floor timer that triggers a losing when expired
- Add show_loss state on the screen for too-few-people and timeout failures
