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/hud.tscn

@@ -1,7 +1,6 @@
-[gd_scene load_steps=3 format=3 uid="uid://cbvi51vvpt7mu"]
+[gd_scene load_steps=2 format=3 uid="uid://cbvi51vvpt7mu"]
 
 [ext_resource type="Script" uid="uid://fpaw3u5yjtbk" path="res://scenes/hud.gd" id="1_64ctp"]
-[ext_resource type="PackedScene" uid="uid://dshaftstrip01" path="res://scenes/shaft_strip.tscn" id="2_shaft"]
 
 [node name="HUD" type="MarginContainer" unique_id=769131693]
 offset_right = 40.0
@@ -31,13 +30,3 @@ text = "FLOOR: 0"
 [node name="ScoreLabel" type="Label" parent="StatsColumn" unique_id=1595653166]
 layout_mode = 2
 theme_override_font_sizes/font_size = 24
-
-[node name="ShaftStrip" parent="." instance=ExtResource("2_shaft")]
-top_level = true
-anchors_preset = 9
-anchor_bottom = 1.0
-offset_left = 12.0
-offset_top = 12.0
-offset_right = 60.0
-offset_bottom = -12.0
-grow_vertical = 2