game: add elapsed time to ui

scenes/main.gd

@@ -2,11 +2,15 @@ extends Node2D
 @onready var main_ui: MainUI = $MainUI
 @onready var main_camera: Camera2D = $MainCamera
 
+var elapsed_time: float = 0.0
 
 func _ready():
 	GlobalConst.sig_debug_camera_zoom.connect(debug_zoom)
 	Engine.time_scale = 1.0
 
+func _process(delta: float) -> void:
+	elapsed_time += delta
+	main_ui.player_ui.set_elapsed_time(elapsed_time)
 
 func _unhandled_input(event: InputEvent) -> void:
 	if event.is_action_pressed("ui_cancel"):