修复了build guard等若干问题

Assets/Editor/PackagingBuildGuard.cs

@@ -27,6 +27,7 @@ public sealed class PackagingBuildGuard : IPreprocessBuildWithReport
         CheckPlayers(problems);
         CheckHeroes(problems);
         CheckSongs(problems);
+        CheckMails(problems);
 
         if (problems.Count == 0)
         {
@@ -156,5 +157,32 @@ public sealed class PackagingBuildGuard : IPreprocessBuildWithReport
             }
         }
     }
+
+    private static void CheckMails(List<string> problems)
+    {
+        foreach (var guid in AssetDatabase.FindAssets("t:mail_so"))
+        {
+            string path = AssetDatabase.GUIDToAssetPath(guid);
+            var so = AssetDatabase.LoadAssetAtPath<mail_so>(path);
+            if (so == null) continue;
+
+            // 跳过 mail_id = 0 的模板文件。
+            if (so.mail_id == 0) continue;
+
+            // 标记未领取（isReceived:0）且携带奖励的邮件 → 新玩家首启会自动领取。
+            if (!so.isReceived && so.rewardList != null && so.rewardList.Count > 0)
+            {
+                int totalRewards = 0;
+                foreach (var reward in so.rewardList)
+                {
+                    totalRewards += reward.reward_ammount;
+                }
+                if (totalRewards > 0)
+                {
+                    problems.Add(path + " :: mail_id=" + so.mail_id + " 未领取且含 " + so.rewardList.Count + " 项奖励（新玩家会自动领取）");
+                }
+            }
+        }
+    }
 }
 #endif