feat(游戏结束): 添加子弹显示名称并改进死亡信息显示

- 为所有子弹类型添加displayName属性用于显示
- 修改GameOver面板显示死亡原因，包含子弹名称和发射者
- 更新死亡原因文本格式为富文本样式
- 移除GameOver面板中多余的LabelSettings资源

scripts/Contents/Panels/GameOver.gd

@@ -1,10 +1,10 @@
 @tool
 extends FullscreenPanelBase
 
-@onready var audio = $"%audio"
-@onready var deadreason = $"%deadreason"
+@onready var audio: AudioStreamPlayer2D = $"%audio"
+@onready var deadreason: RichTextLabel = $"%deadreason"
 
 func beforeOpen(args: Array = []):
 	audio.play()
 	var reasonTemplate = MathTool.randc_from(GameRule.deadReasons)
-	deadreason.text = (reasonTemplate + "凶手是%s。") % args
+	deadreason.text = ("[color=gray]" + reasonTemplate + "凶手是[b]%s[/b]的[b]%s[/b]。[/color]") % args