fix(game): 修复游戏启动器语言设置空指针异常

- 在FCLGameLauncher中添加null检查避免lang为null时的异常
- 验证语言格式确保至少包含两个部分以避免数组越界
- 为GameOption的get方法添加@nullable注解明确返回值可能为空

Author: ShirosakiMio

FCL/src/main/java/com/tungsten/fcl/game/FCLGameLauncher.java

@@ -100,7 +100,9 @@ private void fixLang(GameOption gameOption) {
         boolean toUpper = gameVersion.compareTo("1.11") < 0;
         String lang;
         lang = gameOption.get("lang");
+        if (lang == null) return;
         String[] parts = lang.split("_", 2);
+        if (parts.length != 2) return;
         lang = parts[0] + "_" + (toUpper ? parts[1].toUpperCase() : parts[1].toLowerCase());
         gameOption.set("lang", lang);
     }

FCL/src/main/java/com/tungsten/fcl/setting/GameOption.java

@@ -100,6 +100,7 @@ public void set(String key, List<String> values) {
         parameterMap.put(key, values.toString());
     }
 
+    @Nullable
     public String get(String key) {
         return parameterMap.get(key);
     }