Add currency database, cleanup legacy system

currency_label.gd

@@ -1,7 +1,7 @@
 class_name CurrencyTile
 extends HBoxContainer
 
-@export var currency: Resource = GameState.GOLD_CURRENCY
+@export var currency: Resource
 
 @onready var _icon: TextureRect = $CurrencyIcon
 @onready var _label: Label = $Label
@@ -12,7 +12,10 @@ var _currency_id: StringName = &""
 
 func _ready() -> void:
 	if currency == null:
-		currency = GameState.GOLD_CURRENCY
+		currency = CurrencyDatabase.get_currency_resource(GameState.GOLD_CURRENCY_ID)
+	if currency == null:
+		push_warning("CurrencyTile '%s' has no currency configured." % String(name))
+		return
 
 	_currency_id = GameState.get_currency_id(currency)
 	_label.text = "%s:" % GameState.get_currency_name(_currency_id)