Add virtua hand lighting up floor buttons!

- hand sweeps down the button panel at game start
- button panel now spawns its floor buttons procedurally via button_panel.gd
- elevator_panel waits for the new intro_finished signal before starting floor 1
- removes the stray ShaftStrip from hud.tscn
- cleaned up timing but henry will probably want to tune further

scenes/elevator_panel.gd

@@ -41,7 +41,7 @@ func _ready():
 	_screen.pulse_blocked_perfect.connect(_on_pulse_blocked_perfect)
 	_screen.doors_closing.connect(func(): _on_doors_closing(true))
 
-	EventBus.game_started.connect(_start_floor)
+	EventBus.game_started.connect(_on_game_started)
 	EventBus.game_lost.connect(func(_reason): $SfxRobotIUnderstand.play())
 	EventBus.survivor_squeaked_in.connect(_on_survivor_squeaked_in)
 	EventBus.robot_close_warning.connect(_on_robot_close_warning)
@@ -59,6 +59,10 @@ func _unhandled_input(event):
 			EventBus.debug_starting_floor = EventBus.STARTING_FLOOR
 			get_tree().reload_current_scene()
 
+func _on_game_started():
+	await EventBus.intro_finished
+	_start_floor()
+
 func _reset_floor_state():
 	doors_closing_flag = false
 	people_in_elevator = 0