feat(武器系统): 完善武器获取和提炼逻辑

- 在WeaponShow.gd中修改操作标签文本为"获得武器"和"提炼灵魂"
- 在Feed.gd中添加武器获取逻辑，区分已有武器和新增武器情况
- 在EntityBase.gd中重构武器图标更新逻辑，提取为rebuildWeaponIcons方法

scripts/Statemachine/WeaponShow.gd

@@ -21,12 +21,12 @@ func _ready():
 	nameLabel.text = weaponInstance.displayName
 	soulShow.count = weaponInstance.soulLevel
 	if operation == Operation.GET:
-		operationLabel.text = "获得"
+		operationLabel.text = "获得武器"
 		avatarRect.visible = true
 		nameLabel.visible = true
 		soulShow.visible = false
 	else:
-		operationLabel.text = "提炼"
+		operationLabel.text = "提炼灵魂"
 		avatarRect.visible = false
 		nameLabel.visible = false
 		soulShow.visible = true