Refactor scene structure and resource paths; add death and game over screens

scripts/ui/game_over_screen.gd

@@ -0,0 +1,41 @@
+class_name GameOverScreen
+extends Node
+
+@export var game_over_screen: Control
+@export var restart_button: Button
+@export var main_menu_button: Button
+@export var main_menu_scene: PackedScene
+
+@onready var gm: GM = $"/root/GameManager"
+
+
+func _ready() -> void:
+	if not gm:
+		return
+
+	game_over_screen.hide()
+	restart_button.pressed.connect(on_restart_button_pressed)
+	main_menu_button.pressed.connect(on_main_menu_button_pressed)
+
+
+func on_restart_button_pressed() -> void:
+	if not gm:
+		return
+
+	gm.reset_player_state()
+	get_tree().reload_current_scene()
+
+
+func on_main_menu_button_pressed() -> void:
+	if not gm or not main_menu_scene:
+		return
+
+	gm.reset_player_state()
+	get_tree().change_scene_to(main_menu_scene)
+
+
+func on_player_death() -> void:
+	if not gm or not gm.get_lives() == 0:
+		return
+
+	game_over_screen.show()