feat: 增加NPC范鲸晶

- player场景增加RayCast2D
- 增加npc场景
- 增加NPC对话气泡

scenes/ui/ChatBubble.gd

@@ -0,0 +1,9 @@
+extends Control
+
+@onready var label = $PanelContainer/Label
+
+func set_text(text):
+	label.text = text
+	# Destroy after 5 seconds
+	await get_tree().create_timer(5.0).timeout
+	queue_free()