add collecting coins

scripts/components/score.gd

@@ -0,0 +1,20 @@
+class_name ScoreComponent
+extends Node
+
+@onready var game_manager: GM = $"/root/GameManager"
+
+func _ready():
+    await get_tree().process_frame
+    var coins = get_tree().get_nodes_in_group("coins")
+    
+    for coin in coins:
+        coin.connect("collected", on_collected)
+
+func on_collected(amount: int) -> void:
+    if not game_manager:
+        return
+
+    game_manager.add_coins(amount)
+    print("Coins: ", game_manager.get_coins())
+    # todo: play sound
+    # todo: update ui