Initial scaffold: Godot 4.3 scenes, systems, and placeholders.

Wire all twelve levels with billboard prefabs, autoload systems (inventory, achievements, mock shop, DE/EN/BY), and satire audio locks so the Title→End flow is playable with placeholder assets.

scripts/ui/ui_root.gd

@@ -0,0 +1,161 @@
+extends CanvasLayer
+## Global UI: pause, inventory, shop, settings, toast, dialog, burger-cham.
+
+@onready var pause_panel: PanelContainer = $PausePanel
+@onready var dialog_panel: PanelContainer = $DialogPanel
+@onready var dialog_label: Label = $DialogPanel/Margin/DialogLabel
+@onready var toast_label: Label = $ToastLabel
+@onready var burger_overlay: ColorRect = $BurgerOverlay
+@onready var burger_label: Label = $BurgerOverlay/BurgerLabel
+@onready var points_label: Label = $PausePanel/Margin/VBox/PointsLabel
+@onready var inventory_list: ItemList = $PausePanel/Margin/VBox/InventoryList
+@onready var sfx_slider: HSlider = $PausePanel/Margin/VBox/SfxSlider
+@onready var music_slider: HSlider = $PausePanel/Margin/VBox/MusicSlider
+@onready var lang_option: OptionButton = $PausePanel/Margin/VBox/LangOption
+@onready var hp_label: Label = $HUD/HpLabel
+
+var _dialog_timer: float = 0.0
+
+func _ready() -> void:
+	process_mode = Node.PROCESS_MODE_ALWAYS
+	layer = 100
+	pause_panel.visible = false
+	dialog_panel.visible = false
+	burger_overlay.visible = false
+	toast_label.visible = false
+	_setup_lang_option()
+	_refresh_texts()
+	sfx_slider.value = Settings.sfx_volume
+	music_slider.value = 1.0
+	music_slider.editable = false
+	Achievements.unlocked.connect(_on_achievement)
+	AudioDirector.burger_cham_triggered.connect(_on_burger_cham)
+	Settings.settings_changed.connect(_refresh_texts)
+	Locale.locale_changed.connect(_refresh_texts)
+	Inventory.inventory_changed.connect(_refresh_inventory)
+	Shop.points_changed.connect(_refresh_points)
+	GameState.hp_changed.connect(_on_hp)
+	_on_hp(GameState.hp, GameState.max_hp)
+	_refresh_inventory()
+	_refresh_points(Shop.dressler_points)
+
+func _process(delta: float) -> void:
+	if _dialog_timer > 0.0:
+		_dialog_timer -= delta
+		if _dialog_timer <= 0.0:
+			dialog_panel.visible = false
+
+func _unhandled_input(event: InputEvent) -> void:
+	if event.is_action_pressed("pause_menu"):
+		toggle_pause()
+		get_viewport().set_input_as_handled()
+
+func toggle_pause() -> void:
+	if GameState.current_scene_id in ["title_screen", "death_screen", "intro_cutscene"]:
+		return
+	pause_panel.visible = not pause_panel.visible
+	get_tree().paused = pause_panel.visible
+	if pause_panel.visible:
+		_refresh_texts()
+		_refresh_inventory()
+
+func show_dialog(text: String, duration: float = 3.5) -> void:
+	dialog_label.text = text
+	dialog_panel.visible = true
+	_dialog_timer = duration
+
+func _setup_lang_option() -> void:
+	lang_option.clear()
+	lang_option.add_item("Deutsch", 0)
+	lang_option.add_item("English", 1)
+	lang_option.add_item("Bayerisch", 2)
+	match Settings.language:
+		"en":
+			lang_option.select(1)
+		"by":
+			lang_option.select(2)
+		_:
+			lang_option.select(0)
+
+func _refresh_texts() -> void:
+	$PausePanel/Margin/VBox/TitleLabel.text = Locale.tr_key("menu_settings")
+	$PausePanel/Margin/VBox/ResumeButton.text = Locale.tr_key("menu_resume")
+	$PausePanel/Margin/VBox/ShopTitle.text = Locale.tr_key("menu_shop")
+	$PausePanel/Margin/VBox/BuyPointButton.text = Locale.tr_key("menu_buy_point")
+	$PausePanel/Margin/VBox/BuySunglassesButton.text = Locale.tr_key("shop_sunglasses")
+	$PausePanel/Margin/VBox/BuyTicketButton.text = Locale.tr_key("shop_ticket")
+	$PausePanel/Margin/VBox/BuyMilkButton.text = Locale.tr_key("shop_milk")
+	$PausePanel/Margin/VBox/BuyTiramisuButton.text = Locale.tr_key("shop_tiramisu")
+	$PausePanel/Margin/VBox/SfxLabel.text = Locale.tr_key("menu_sfx")
+	$PausePanel/Margin/VBox/MusicLabel.text = Locale.tr_key("menu_music")
+	$PausePanel/Margin/VBox/LangLabel.text = Locale.tr_key("menu_language")
+	$PausePanel/Margin/VBox/InventoryLabel.text = Locale.tr_key("menu_inventory")
+	_refresh_points(Shop.dressler_points)
+
+func _refresh_points(points: int) -> void:
+	points_label.text = Locale.tr_key("menu_points", [str(points)])
+
+func _refresh_inventory() -> void:
+	inventory_list.clear()
+	var items := Inventory.get_all()
+	for id in items.keys():
+		var count: int = int(items[id])
+		var item_name: String = Locale.tr_key("item_" + str(id))
+		inventory_list.add_item("%s x%d" % [item_name, count])
+		inventory_list.set_item_metadata(inventory_list.item_count - 1, id)
+
+func _on_hp(hp: int, max_hp: int) -> void:
+	hp_label.text = "HP %d/%d" % [hp, max_hp]
+
+func _on_achievement(_id: String, title: String) -> void:
+	toast_label.text = Locale.tr_key("toast_achievement", [title])
+	toast_label.visible = true
+	await get_tree().create_timer(3.0).timeout
+	toast_label.visible = false
+
+func _on_burger_cham() -> void:
+	burger_label.text = Locale.tr_key("burger_cham")
+	burger_overlay.visible = true
+	await get_tree().create_timer(2.5).timeout
+	burger_overlay.visible = false
+
+func _on_resume_pressed() -> void:
+	pause_panel.visible = false
+	get_tree().paused = false
+
+func _on_buy_point() -> void:
+	Shop.purchase("buy_point")
+
+func _on_buy_sunglasses() -> void:
+	Shop.purchase("sunglasses")
+
+func _on_buy_ticket() -> void:
+	Shop.purchase("death_ticket")
+
+func _on_buy_milk() -> void:
+	Shop.purchase("milk")
+
+func _on_buy_tiramisu() -> void:
+	Shop.purchase("tiramisu")
+
+func _on_sfx_changed(value: float) -> void:
+	Settings.set_sfx_volume(value)
+
+func _on_music_changed(_value: float) -> void:
+	Settings.set_music_volume(1.0)
+	music_slider.value = 1.0
+
+func _on_lang_selected(index: int) -> void:
+	match index:
+		1:
+			Settings.set_language("en")
+		2:
+			Settings.set_language("by")
+		_:
+			Settings.set_language("de")
+
+func _on_inventory_activated(index: int) -> void:
+	var id: Variant = inventory_list.get_item_metadata(index)
+	if typeof(id) == TYPE_STRING:
+		Inventory.use_item(str(id))
+		_refresh_inventory()