feat: 1. 添加武器基础脚本

2. 添加武器基本resources
3. 武器碰撞 RangeArea 进入和退出检测
4. 添加 Hitbox 进行武器碰撞敌人区域（只是添加了，功能还没实现）
5. 武器冷却时间 weapon_base / CooldownTimer

scenes/weapons/weapon.gd

@@ -0,0 +1,36 @@
+extends Node2D
+class_name Weapon
+
+
+@onready var sprite_2d: Sprite2D = $Sprite2D
+@onready var collision: CollisionShape2D = %CollisionShape2D
+@onready var cooldown_timer: Timer = $CooldownTimer
+
+var data: ItemWeapon
+var is_attacking := false
+var atk_start_pos: Vector2
+var targets: Array[Enemy]
+var closest_target: Enemy
+var weapon_spread: float
+
+func _ready() -> void:
+	atk_start_pos = sprite_2d.position
+	
+
+func setup_weapon(data: ItemWeapon) -> void:
+	self.data = data
+	collision.shape.radius = data.stats.max_range
+	
+
+func can_use_weapon() -> bool:
+	return cooldown_timer.is_stopped() and closest_target
+
+
+func _on_range_area_area_entered(area: Area2D) -> void:
+	targets.push_back(area)
+
+
+func _on_range_area_area_exited(area: Area2D) -> void:
+	targets.erase(area)
+	if targets.size() == 0:
+		closest_target = null